Dark Heresy fluff bucket...

[Piksi]

Poshto je Dark Heresy fluff rasut na sve strane interneta hteo bih da ovde ostavljate sve shto ste sakupili o Warhammeru 40k shto moze da sluzi game masterima a da se ne nalazi vec u knjigama. Pocecu ja sa po meni solidno odradjenim time lineom Uzivajte i nadam se da ce nekome ovo koristiti.



circa 60,000,000 B.C. - The Necrontyr wage war against the Old Ones out of jealousy over that ancient species' long lifespans and extraordinary accomplishments, a conflict later called the War in Heaven by the Eldar. The Necrontyr begin to lose this war because of the Old Ones' psychic abilities and more advanced technology and contact the intelligent energy beings called the C'tan for aid. In turn, the C'tan have the Necrontyr create exoskeletons for them from the living metal called necrodermis so that they can interact with solid matter. The C'tan also trick the Necrontur into transferring their own consciousnesses into robotic bodies created from necrodermis which ultimately results in their becoming the C'tan's new race of non-sentient slaves called the Necrons. The newly-created Necrons then purge almost all life from the Milky Way in order to feed the C'tan.

The Old Ones' civilization collapses under the assault of the Necrons and that ancient species seemingly dies out. The amphibious Slann, the premier servant species of the Old Ones, presciently warn the Eldar of their own fall to Chaos millennia in the future.

10,000 B.C. - The last Ice Age on Terra comes to an end and the Neolithic Age begins. The Agricultural Revolution is initiated in the ancient Middle East in the region that will be called the Fertile Crescent. Humans first begin to settle in towns and give up their previous nomadic hunter-gatherer existences.

8,000 B.C. - 1400 A.D. - Birth of the Ruinous Powers within the Warp known as Nurgle the Plague Lord, Khorne the Blood God, and Tzeentch, the Changer of Ways, in that order. These entities, colloquially called the Chaos Gods, were created and empowered by the collective psychic imprint of humanity and the other intelligent races of the Milky Way Galaxy on the once tranquil Immaterium, transforming it into the daemon-haunted nightmare that is the Warp of today.

8,000 B.C. - 1400 A.D. - The Eldar learn the arcane secrets of Warp tunnel technology from the Old Ones, who created them to serve as a psychic warrior species during the War in Heaven, and proceed to construct the Webway by "structuring" certain portions of the Warp.

8th Millennium B.C. - Birth of the future Emperor of Mankind somewhere in central Anatolia after all the known shamans of the Earth, those few members of humanity blessed with psychic abilities at this point in mankind's history, collectively commit suicide and combine their life energies within the Warp into a single soul that is reincarnated in the body of an extraordinary human being, the most potent psyker in the Milky Way Galaxy who will prove to be immortal. The future Emperor will help guide humanity throughout the long millennia to come, often taking on the identity of some of the most famous personages in human history in order to move the species along a particular path. It will not be until the terrible times of the Age of Strife almost drive humanity to extinction that the Emperor decides to take a more active stance in human affairs to help guide the race through the terrible birth pangs of becoming a fully-psychic species.

The Age of Terra, also sometimes called the Age of Progress in older Imperial texts, is the era of human history between the 1st and 15th Millennia (1 - 14,000 AD) when humanity advanced from a pre-industrial Iron Age culture to become a star-spanning Fusion Age civilization. The original reason for numbering the years from this point, that it was believed to be the year of the birth of Jesus Christ, has long been forgotten by humanity, which now possesses only one religion -- a deep faith in the God-Emperor of Mankind and his Imperial Cult. During the long years of the Age of Terra, humanity comes to dominate the Earth culturally and technologically. Civilisations come and go. The Solar System is ultimately colonised once humanity develops the necessary technology to leave the Earth's orbit in the late 2nd Millennium and the early 3rd Millennium. Mankind colonises Mars and lives on the moons of Jupiter, Saturn and Neptune. Advanced fusion and anti-matter propulsion technology is developed which eventually allows humanity to construct interstellar starships that can colonize other star systems. At the very end of the period in the 15th Millennium and stretching into the next era in human history, the Age of Technology, humanity begins to colonise the stars using these sub-light spacecraft. At first only nearby star systems can be reached and the human colonies established on them must survive as independent states since they are separated from Earth by up to ten generations of travel. Almost nothing of this period's events is known to current Imperial historians, though it is known that the Emperor was alive and on Earth throughout this period, disguising his true abilities and immortal nature as he moved from identity to identity, always trying to better the lot of humanity, physically, intellectually and spiritually.


006.M2 - Battle of Hastings fought in northwestern Terra, beginning a long series of events culminating in the Industrial Revolution.

750 - 900.M2 - Industrial Revolution begins in the Western regions of Terra and eventually spreads across the planet by the first decades of the 3rd Millennium.

914918.M2 - First industrialized global war known as World War I begins in the Western regions of Terra.

939-945.M2 - Second industrialised global war, called World War II, a conflict even more devastating than the first, engulfs Terra.

945.M2 - Detonation of the first human-developed atomic weapon. Fission-based nuclear power soon becomes widespread on Terra as do stockpiles of nuclear weapons.

946.M2 - First digital computer, called UNIVAC, invented by humans on Terra in the long-lost ancient city of Philadelphia.

961.M2 - First human being, Yuri Gargarin, crosses Terra's atmosphere and orbits the planet.

969.M2 - First human landing on Luna.

971.M2 - First space station, called Salyut, is placed in orbit of Terra.

001.M3 Mankind's scientists unlock the human genome, allowing for significant advances in genetic research.

100.M3 Mars is terraformed and made habitable for human habitation over several centuries beginning in the year 2100 A.D.
Scientific advances of the third and subsequent millennia bring some basic knowledge of the Warp to humans.
Humanity begins to colonise the Solar System using conventional sub-light spacecraft. Colonies are established on Mars, and on the moons of Jupiter, Saturn, and Neptune. This is the full extent of mankind's domains across the Milky Way Galaxy until the 15th Millennium.
Humanity uses Ohnyl Cylinders (O'Neill Space Colonies) to spread beyond its own home solar system to local habitable planets in other nearby star systems, however, such early interstellar colonies would not make contact with Terra until millennia later.

000.M4 The Warp discovered.

The 5th Millennium saw much of mankind's early sublight interstellar expansion outside of the Sol System. It was during this millennium that the Alpha Centauri System, the closest star system to Earth's own, was colonized and terraformed by the earliest human settlers.

[Piksi]

The Dark Age of Technology was the zenith of mankind's scientific knowledge and technological power in the Milky Way Galaxy. Even tens of millennia later, mankind has not been able to equal or regain its former height of achievement. This age occurred long before the current Age of the Imperium and knowledge of this time period is now incredibly sparse, and many "facts" about it are no more than legend.
Although a "golden age" for humanity in terms of scientific achievement, because of the catastrophic effects of the following Age of Strife in which so many of the technologies developed in this era were used to cause massive destruction and suffering on countless human-settled worlds, mankind has since come to regard scientific knowledge as an abhorrent and dangerous commodity. The lost Age of Technology is thus considered "dark" in the Imperium's current era. It is also considered a dark age in the minds of the Ecclesiarchy because mankind in the Age of Technology had come to worship science as a god, and the God-Emperor had not yet revealed himself to humanity.

Stelar Exodus

The Stellar Exodus was humanity's earliest interstellar colonization of other worlds beyond the Solar System, actually taking place before the Age of Technology officially began. Humanity initially established colonies within Terra's solar system. Spacecraft were still only capable of sub-light speeds at this time. Voyages beyond the Solar System took generations and the colonies that were established were effectively isolated from each other and from Terra. Interstellar trade was therefore severely restricted. This forced the individual colonized star systems to be completely self-sufficient in all of their vital requirements (food, medicine, technology, etc) and allowed them to develop distinctive languages and cultures.

The Warp Drive

The Age of Technology finally brought the development of the Warp Drive and the Geller Field, allowing spacecraft to make short warp jumps, traveling vast interstellar distances in a relatively short amount of time. One can compare this early human form of faster-than-light travel to the way that Tau starships currently travel, described as 'skimming the surface' of the Warp.
The Warp Drive's development greatly accelerated the human colonization of the Milky Way Galaxy, and for the first time allowed trade and communications between the human colonies and the homeworld of mankind, Terra.

Navigators

The second vital development of the Age of Technology was the creation of the psychic Navigator gene and the birth of the mutant Navigators, mildly psychic humans with a "third eye" of perception who could see into the currents of the Warp and navigate a course through them. This allowed human spacecraft to make longer and more accurate Warp jumps than previously possible when relying wholly upon a computer for navigation in the chaotic realm of the Immaterium.

The STC and the Emergence of Pyskers

Of major importance to the era and humanity in general was the invention of the Standard Template Construct (STC) system. These highly advanced computer databases allowed human colonies to maintain an advanced technological level. The STCs contained all human scientific and technological knowledge of the era and provided the instructions required to build anything the colonists might need. As most colonists lived relatively simple lives and required only basic equipment, the more advanced technology available in a full STC was rarely utilized.
The resulting exploration of the galaxy brought mankind new knowledge, wealth and arrogance. Science is said to have become humanity's new God, replacing in importance all previous religions. Humanity encountered several intelligent alien races during their expansion out into the galaxy. With these discoveries began in time the first human-alien wars. With mankind at the height of its power, the threat of aliens was viewed as trivial and eventually non-aggression pacts were signed between Terra, its colonies and the alien races.

At this time, after the discovery of Warp Drive allowed interstellar transportation, commerce and communications to develop, the human colonies were politicaly united with Terra in some form of federated government, thus allowing the human race to remain unified and powerful.

It was during the Age of Technology that psykers were first scientifically verified to exist, after long millennia of legend, rumor and pseudoscience in which the scienftific establishment simply could not prove the existence of psychic powers among humans. It is, however, unexplained how these early human psykers avoided the danger of daemonic possession for thousands of years, which would have led to the destruction of entire worlds as later happened during the Age of Strife. Whether daemons and the Ruinous Powers were less prevalent or potent in the Warp in this time before Slaanesh's birth is unknown.

Where at first the gift of the psychic mutation was limited to only a few individuals in every human population (who often fell victim to superstitious suppression), towards the end of the Age of Technology, psykers suddenly began appearing in unusually great numbers, on every human world. On the more progressive and technologically advanced human colonies, these psykers - at least until the threat of daemonic possession became apparent - were protected by law and allowed to develop and explore their abilities. On other, less sophisticated human worlds, they were often killed in literal witch-hunts and anti-psyker pogroms.

The Men of Iron

One of the reasons humanity was so successful at conquering a large part of the galaxy was the development of the artificially intelligent humanoid constructs now only known as the Men of Iron. These powerful and fully autonomous labour and combat robots won many wars for humanity, but for some unknown reason turned against their masters at the end of the Dark Age of Technology and unleashed a terrible war upon their human masters. This conflict was eventually won by humanity, but at a great cost. The damage to interstellar human society was catastrophic and shattered much of humanity's hard-won economic strength and political unity.

The End of the Golden Age

This Golden Age for humanity would not last. Warp travel became increasingly difficult and ultimately impossible due to the great Immaterium Warp Storms that would herald the violent birth of the Chaos God Slaanesh and the Fall of the Eldar. Trade and communication between the human colonies eventually collapsed, restoring the isolation of human colony worlds. With this relative isolation Abhumans (i.e. new human mutant subspecies adapted to their environments) like the Ogryns, Ratlings, and Squats developed on several planets in the galaxy.
Certain planets, like Terra, the ancient homeworld of mankind - which relied heavily on trade with the rest of humanity - were suddenly unable to feed their enormous populations. Hunger and starvation followed. The human psykers were relatively weak and inexperienced, and at constant risk of possession by daemons and other Warp entities after the great Warp storms began. The sudden impossibility of Warp travel meant that the once unified interstellar human federation broke apart into completely isolated star systems and worlds. Daemonic possession, widespread insanity and isolation led to inter-human conflict, utter anarchy and the regression of most human civilizations to barbarity. The time period following the Dark Age of Technology is thus aptly named the Age of Strife by the savants of the Imperium.

[Piksi]

The Age of Strife is the name for the chaotic period of human history between the 25th and 30th Millenniums.
According to the "official" histories of the Imperium, the precise details and dates of the Age of Strife are not known, due to data having been lost over vast amounts of time, to the chaos of that period, and partly to censorship by various Imperial authorities.

Dark Age of Technology

The Dark Age of Technology is the name given to the period of human history that began in the 15th Millennium and ended in the 25th Millennium, during which huge advances occurred in human science and technology. The Dark Age of Technology saw the development of the specialized psychic mutants known as Navigators and the earliest use of the Warp for space travel by human beings, with the greatest extent of interstellar space exploration and colonisation across the galaxy taking place during this period. Other notable developments include the development of the Standard Template Construct (STC) system and the artificially-intelligent Iron Men, powerful combat robots.
The Age of Technology ended in inter-human war and anarchy, in an era known as the Age of Strife, as massive Warp storms cut off interstellar travel and communications across the whole of the human-settled galaxy. The STC systems lapsed into disuse or decayed. The Adeptus Mechanicus have made finding a functional, untainted STC system their ultimate goal and are willing to go to any lengths to find even the smallest printout of technology from an STC.

Causes and Beginning

During the so-called "Dark Age of Technology" humanity had reached its technological peak. The "Standard Template Construct", or STC, had been perfected by human scientists and engineers and allowed an unprecedented expansion of humanity throughout the galaxy.
One of the reasons humanity was so successful at conquering a large part of the galaxy was the development of the artificially intelligent humanoid constructs now only known as the Men of Iron. These powerful and fully autonomous labour and combat robots won many wars for humanity, but for some reason turned against their masters at the end of the Dark Age of Technology. The war was eventually won by humanity, but at a great cost. The damage was catastrophic and had shattered much of humanity's power. Unfortunately, this was only the beginning of mankind's misfortunes.

As humanity became widely dispersed across the galaxy during the Age of Technology, the ancient Eldar Empire began its decline; the great success of the advanced Eldar race had led to decadence and hedonism on a grand scale. Within the immaterial, psychic universe of the Warp, the spiritual corruption of the Eldar civilization was reflected in the forming of a new Chaos God, Slaanesh, which in turn caused massive disturbances in the Warp; parts of the galaxy became isolated by these Warp storms, making Warp travel and communication impossible, cutting off many human colony worlds from one another, including those of the Solar System.

Towards the end of the Age of Technology psykers first appeared among humanity. While persecuted on many backwards, regressive human worlds as witches, in enlightened and progressive societies these psykers were at first protected and accepted. The intolerance of psykers would seem prescient, as many human worlds fell to the dominance of daemons and other Warp creatures using possessed psykers as gateways into the physical world. Only worlds which had rigorously suppressed psykers survived.

The Age of Strife followed the Age of Technology, as human civilisation collapsed in widespread insanity, daemonic possession, anarchy and inter-human civil war. Terrible weapons of the golden age of technology were unleashed, devastating many human colonies and turning once-verdant worlds such as Baal Secundus into irradiated desert planets. Many isolated and vulnerable human-colonized worlds also became prey to hostile alien races, such as the Orks.

In a relatively short span of time, the once galaxy-spanning human civilization was brought to its knees, and was forced to endure nearly five millennia of anarchy, terror, war, genocide and slavery. Other than tales of great suffering, little information has survived this dark time to be known to the men and women of the Imperium.

Earth and Mars

Earth and the rest of the settled worlds of the Solar System were surrounded by terrible Warp storms, isolating the human homeworld for several thousand years from the rest of the galaxy. Control of the Solar System shifted constantly between the worlds of Earth and Mars during the first half of the Age of Strife. By the 28th Millennium almost all traces of civilization on Earth were long gone; instead, techno-barbarians battled one another over the scraps of the ancient human civilization. Little information remains from this dark time, but it is known that tyrants such as Kalagann of Ursh (northern Asia/Russia), Cardinal Tang, and ("the half-mad, half-genius") Narthan Dume of the Panpacific Empire ruled during this era. Other known Earth nations of the time period include the Yndonesic Bloc, the Urals (a centre of industry), the Jermani, Gyptus, Merica, Afrique, the Terrawatt Clan and Alba. Another ethnicity mentioned are the 'Nordyc' people.
Mars underwent a very different transformation. After a brief period of anarchy, the tech-priests of the Adeptus Mechanicus emerged victorious over the psyker mutants and unified their homeworld beneath their theocratic rule. The tech-priests then visited Earth but were appalled at the destruction there and saw nothing worth saving. Instead, the Martians studied the Warp and after many lifetimes learned to detect 'lulls' in the Warp storms. At the same time the immense robotic fighting machines known as Titans were created, to defend the Red Planet.

For over a thousand years the Cult Mechanicus watched and waited. Whenever a break in the Warp storms occurred, an expedition was sent, complete with a full Titan Legion and thousands of servitors and tech-priests. Some of these expeditions were lost in the Warp or died on faraway worlds. Others succeeded in establishing 'Forge Worlds' - replicas of Mars. Broken messages were transmitted to Mars, but it was not until the time of the Great Crusade that the Forge Worlds and Mars would be reunited.

The End of the Age, and the Rise of the Emperor

Eventually, an immensely powerful human leader and psyker known as the Emperor divined that the final birth of Slaanesh was nearing, as well as the effect this birth would have on the galaxy and he began to accelerate his preparations for this galaxy-changing event. From the beginning of the Age of Strife the Emperor had no longer been content with guiding humanity from the shadows. If his species was to survive, he would have to take charge himself, openly and without subterfuge. Within his underground gene-labs beneath the Himalayas, the Emperor began to experiment on the human genetic code. Using his own DNA as a template he created the nineteen geneseed organs of the Space Marines. Through deeds of great valour and his own personal charisma, the Emperor recruited from the techno-barbarians that wandered Terra's surface and implanted the geneseed into them, turning them into the geno-warriors. Once he had gathered sufficient military forces, he conquered Earth and later its satellite of Luna, and began the genetic engineering processes necessary to create the Primarchs and, from the Primarchs' own genes and the genetic blueprints of his geno-warriors, the Space Marine Legions.
Upon the birth of Slaanesh sometime in the early 31st Millennium, the crippling Warp storms ended (which allowed for easier galactic travel), the Eldar race was nearly annihilated and its hold over much of the galaxy was lost, and the Emperor began to carry out his plans to reunify humankind under his rule. With the Emperor's ascension and the creation of the Imperium of Man in a political and military alliance between Terra and Mars, the Age of Strife was finally ended and a new age had begun. This brief age of conquest, heroism and unity would be known as the Great Crusade, and it would in turn end with the terrible tragedy of the Horus Heresy.

Legacy

The Age of Strife had a tremendous impact on human civilization. Humanity barely survived the period, and most of the knowledge of the previous golden era was lost, much of it irrevocably; in particular, the loss of the STC system is seen as a serious setback for the advancement of the Imperium. The Adeptus Mechanicus regards the STC as holy and constantly searches for remnants of STC systems. Although much lost information has been recovered by the efforts of the Adeptus Mechanicus, by focusing on re-attaining knowledge from the ancient STC and spending little energy inventing new technology, the Imperium advances at only a snail's pace technologically. This is further compounded by the centralization of knowledge in the hands of the Adeptus Mechanicus, preventing the dissemination of known science and technology that might speed up the process of innovation.
Humanity as a whole became more superstitious and distrustful because of the horrors perpetrated during the Age of Strife, something which the Imperial government goes to great lengths to encourage. In particular, the Imperium's people distrust mutants, aliens and psykers; this distrust runs so deep that the Imperium has a complex secret police force, known collectively as the Inquisition, devoted to finding and destroying all aliens, daemons, mutants, unsanctioned psykers and "heretics" (anyone deemed to be straying from official Imperial doctrine) existing within the Imperium. Despite the general distrust of psykers, they perform many critical functions for the Imperium, most notably the maintenance of the Astronomican, so they are often rounded up by Imperial agents and forced into service. The Adeptus Ministorum ("the Ecclesiarchy"), the official religious hierarchy of the Imperium, enforces a strict dogma including absolute devotion to the Immortal God-Emperor of Mankind, the embodiment of Jehovah, Jesus Christ, Allah, the Buddha, Brahma and every other divinity ever worshipped by humanity, all rolled up into a single personage.

In short, the authoritarian, often harsh Imperium of Man possesses its unique characteristics in large part due to the great suffering endured by humanity during the Age of Strife.

[Piksi]

Great Crusade

The Great Crusade is a historical period, lasting from the late 30th into the early 31st Millennium (approximately a little over two centuries). The Great Crusade marked was a brief era in human history of rebuilding and reunification following the complete regression of mankind into techno-barbarism during the Age of Strife. It was a time when the Emperor of Mankind still lived in the conventional sense and led his race in person. The Emperor of Mankind sought to unite all of humanity under one banner following the Long Night of the Age of Strife, and end inter-human conflict. Once united, the Emperor intended to begin the next stage of his great plan to ensure human domination of the galaxy. To carry out the Great Crusade and reunite all the scattered colony worlds of Mankind beneath the single banner of the Imperium of Man, the Emperor created the Space Marine Legions of the Adeptus Astartes and the Imperial Army to bring the light of Imperial Truth and enforce Imperial Compliance with the new regime on every human world encountered. At its peak in the early 31st Millennium some 203 standard years after it began, there were 4,287 primary Expedition Fleets engaged upon the business of enforcing Imperial Compliance and extending the Imperial aegis across the galaxy as well as 60,000+ secondary deployment groups involved in regulating Compliance or Imperial occupations. A further 372 Expedition Fleets were regrouping or refitting in the Sol System or other Imperial hub star systems or resupplying as they awaited new orders. Some 4.3 million remembrancers, official Imperial journalists, were sent out with these fleets in the final days of the Great Crusade. Finall, every Imperial Expedition Fleet carried with it a corps of iterators, Imperial philosophers, rhetoricians and propagandists who sought to spread the Imperial Truth to every human world.

Beginnings

During the Age of Strife the Emperor, who had spent his near-immortal life guiding and influencing mankind, was trapped on Earth, due to Warp storms. Not content to sit on his laurels, the Emperor of Mankind spent this time performing biological research on the human genetic code. The result of this work was the creation of the first prototype super soldiers later known as Space Marines. Using these first Space Marines, the Emperor united the tribes of Terra under one government. This event was later known as the Unification. After this, the Emperor realised that to reunite all of humanity, he would need generals in addition to himself. So he ordered the creation of 20 highly advanced, genetically engineered super humans known as the Primarchs. These super humans, created from the Emperor's own genetic stock, were intended to be the next stage in human evolution. The powers of Chaos, however, managed to infiltrate the Emperor's secret laboratory, teleporting the unborn Primarchs away from Earth. The Emperor however was still able to use his own genetic template to create more space marines and keep the geneseed pure.

The End of the Age of Strife

After five millennia, the Warp storms had dissipated from Earth. With their absence allowing interstellar travel once again, the Emperor moved forward with his plans.

Mars and the Adeptus Mechanicus

The Emperor's first obstacle was the existence of the empire of the Techpriests of Mars, who had historically been fiercely independent of Earth. Instead of an outright war, the Emperor used the threat of his Space Marines to form an alliance with the techpriests of the Adeptus Mechanicus on Mars. Despite his disdain for their reliance on religion and cybernetics, the Emperor knew that he would need Mars' factories, mechanical output and ancient technological know-how to unify humanity, and he incorporated them into the Imperium. The Techpriests of Mars, likewise, saw the Emperor's scientific background as proof that he was the Machine God (or Omnissiah), which their religion had promised would return one day to the Red Planet and offer the way forward for humanity.

Rediscovery of the Primarchs

Expansion from Earth was slow, primarily due to reasons of manpower. Without the Primarchs, the time required to create a Space Marine was far longer than ideal. This and the fact that the Emperor was adamant that the material for new geneseed must come directly from him, to keep the organs pure and 100% effective. After a time, the Emperor was reunited with one of his Primarchs in the Cthonian system: Horus. Being the first Primarch (and, in some ways, his first son), Horus and the Emperor formed a truly unique bond, saving one another's' lives on many occasions. With the increased Space Marine production, the Great Crusade began picking up steam, with the Emperor's "United Human Empire" attracting entire planets to his cause. After 30 years of successful Crusading, the Emperor discovered another of the Primarchs. Although Horus was pleased at the discovery of one of his brothers, he secretly pledged to always be the Emperor's favorite son, no matter what else. Over time, all of the Primarchs were rediscovered and given command of the Space Marine legion for which their genetic code was the basis. With the rediscovery of the Primarchs, Space Marine production was drastically decreased in time; a Space Marine could be made in as little as a year. This rapid creation, it should be noted, would prove disastrous: mental defects and unique eccentricities crept into the ranks.

Fractures in Loyalty

As the Imperium grew (and there was a lesser need for a single crusading army), the Primarchs and their Emperor began to grow distant from each other. The Night Lords and World Eaters Legions grew infamous for their ever-greater atrocities, the Thousand Sons' pursuit of knowledge turned into dabbling with sorcery, and the Word Bearers fanatical religious beliefs led to a rift between them and the Emperor when he rejected their worship. The Imperial Army, composed almost entirely of normal human soldiers (some regiments such as the Geno Two-Five Chilliad were selectively bred to produce more capable soldiers or officers), provided much-needed manpower for garrison and support duties for the planets conquered by the Crusade. Freed from garrison duties, Space Marines could conquer yet more worlds in a shorter space of time. Many Marines and Guardsmen began speaking only of their loyalty to their Primarch, not their Emperor. Owing to the isolation between the Legions and the Emperor, this essentially went unnoticed.

Twilight of the Great Crusade

After Horus' successful campaign to destroy the largest Ork WAAAGH! known in the history of the Imperium to that point at the world of Ullanor, the Emperor declared it the greatest victory of the Imperium to date. Horus' reward was the title of Warmaster, with it the supreme command of the Imperium's Military. After doing so, the Emperor made it known that he was needed on Terra, where he would begin his next phase for human evolution. Horus was not informed of the Emperor's plans on Terra, and felt troubled by that. To make matters worse, while some of his fellow Primarchs accepted his promotion, others, chiefly Angron, Night Haunter and Perturabo, openly begrudged Horus his new authority. There was also the widespread belief that the Emperor would disband or reduce the Space Marine legions to the level of peacekeeping forces. Horus resented his brothers' feelings and thought that while he was winning the Imperium the Emperor was just pursuing Godhood, which was all the powers of Chaos needed to sow the seeds of dissension into his mind. Over time, the whispers of the Dark Gods convinced Horus to attempt to take control of the Imperium from the Emperor, an event known as the Horus Heresy. The Heresy would end with the death of Horus, the exile of his traitor Legions, and the quasi-death of the Emperor of Man.

[Piksi]

The Horus Heresy

The Horus Heresy was a galaxy-spanning civil war that marked the end of the Emperor of Mankind's Great Crusade to reunite the scattered colony worlds of humanity under a single government and the true beginning of the current Age of the Imperium. The Horus Heresy is in many ways the true founding event of the Imperium of Man as it now exists. The conflict was fought across the Milky Way Galaxy in the early 31st Millennium and resulted in more than 2.3 trillion dead as well as the death of Horus, the internment of the Emperor of Mankind in the Golden Throne, the creation of the Chaos Space Marine Traitor Legions and the birth of the present day structure of the Space Marine Chapters following the Second Founding and the Reformation of the Imperium by the Ultramarines' Primarch Roboute Guilliman.

The Great Crusade

When the great Warp Storms that had cut off Terra since the end of the Dark Age of Technology subsided, and the Age of Strife came to an end at the dawn of the 31st Millennium, the Emperor of Mankind deemed it time to begin his Great Crusade, a massive galactic campaign by which he and his armies would free all human-settled colony worlds from alien oppression or primitive ignorance and reunite the human race across the galaxy under the single banner of the new Imperium of Man. To execute this plan, the Emperor created the Primarchs, his god-like, genetically-engineered superhuman offspring. The Primarchs were still in their infancy, growing to hyper-accelerated maturity in their special gestation tanks, however, when they were snatched away from the special genetic laboratory deep beneath the Himalayan Mountains on Terra where they had been created and gestated by the Emperor himself using his own DNA. The cause of this disappearance was the Chaos Gods, who were fearful that with the Primarchs the Emperor would be able to impose Order across the galaxy and weaken their own firm grip on the collective unconsciousness of the minds of men. Uniting their powers, they opened a portal from the Warp and broke into the laboratory through the psychic wards the Emperor had erected to prevent their intrusion and, unable to destroy the Primarchs outright because of the wards the Emperor had laid upon them, instead chose to scatter them through the Warp across the galaxy, where they eventually came to rest on diverse, human-inhabited worlds. It was at this time that the Ruinous Powers first touched the souls of those Primarchs who would eventually turn to the worship of Chaos, infecting them with a shard of corruption. Certainly the fact that each of the Primarchs was ultimately cast ashore on a habitable world settled by humans was no accident; the Chaos Gods may have hoped that by having the Primarchs raised among men without the guidance of the Emperor they would display more of the human weaknesses that would make them easier to corrupt when the time came.
During the Great Crusade, the Emperor encountered each of the Primarchs on their scattered homeworlds in turn. To fill the gap in his military plans for the Great Crusade wrought by the Primarchs' absence, the Emperor had decided instead to found 20 Space Marine Legions. The Emperor used the Primarchs' genetic material still in his possession to craft the genetically-enhanced warriors of each Legion. After the Emperor rediscovered his sons he deemed it fitting that each Primarch should lead their genetic offspring as the commander of the Legion whose Astartes bore their DNA. However, this would prove a critical mistake, as the Space Marine gene-seed creation process made the Emperor, the Primarchs and the Space Marines analogous to Grandfather, Fathers and Sons, respectively, in their genetic inheritance and superhuman abilities. In time, many of the Space Marines in the Legions, especially those recruited from their Primarchs' homeworld rather than from Terra before the Primarchs' rediscovery, would come to venerate and feel more loyalty for their Primarch than the Emperor of Mankind, another weakness that was exploited by the Ruinous Powers.

After more than 200 years of hard conflict in the early 31st Millennium, over two million human-settled worlds across the Milky Way Galaxy had been reclaimed by the Emperor in the name of the Imperium of Man. Beside him had stood the Primarch Horus, who had fought alongside the Emperor for the early part of the Great Crusade as his only rediscovered son and primary military commander, glorying in the attentions of his father. The long wars had forged a strong bond between them, and they were truly a father and son. But now the Emperor had to consolidate his newborn Imperium, and undertake the next phase of his Grand Plan, the creation of a Webway through the Immaterium much like that used by the Eldar that would be open to humanity by wielding the psychic augmentation technology of the artefact from the Dark Age of Technology known as the Golden Throne. This work required his continued presence on Terra, and so after Horus' magnificent victory in the Ullanor Crusade, against the largest horde of Orks ever encountered in the galaxy at that time, the Emperor departed and left Horus in charge of the Great Crusade with the exclusive title of "Warmaster." Horus was now the Commander-in-Chief of all of the Imperium of Man's armies, charged with leading the other Primarchs and their Legions through the remainder of the Great Crusade.

At this announcement there was much shock and outrage. Many of the other Primarchs did not understand why the Emperor was leaving them to fight the enemies of Mankind alone and, worse still, why Horus should be raised as the first among equals over all of the other Primarchs to take command over them. Rogal Dorn, Sanguinius and Fulgrim were pleased for their brother, the new Warmaster, while others - such as Angron, Roboute Guilliman, Lion El'Jonson and Perturabo - all reacted with varying degrees of disapproval. The situation only grew worse when the Emperor announced that he would be creating a civilian administrative bureaucracy known as the Council of Terra to carry out the day-to-day governmental affairs of the Imperium, replacing the direct rule of the Emperor while he was engaged in his secret Webway Project and relegating the Primarchs to a primarily military role as the Imperium's most preeminent commanders. Many of the Primarchs, including Horus, were deeply disturbed that their father would make them subject to normal men and women who had never shed blood in the establishment or expansion of the Imperium and that he would remove them from the political positions of rule to which they believed that their great talents, energy and achievements entitled them. The Emperor had sought to create a civilian bureaucracy for the Imperium precisely because he wanted regular human beings to learn to govern themselves once more and not become beholden to a permanent, genetically-enhanced ruling class, but the Chaos Gods would ultimately use the Primarchs' resentment as one of the all-too-human weaknesses they could exploit to corrupt half of their number.

The Corruption of the Astartes Legions

During the Great Crusade, it became apparent that the Primarchs were far from the perfect specimens of humanity they were intended to be. Although each Primarch was physically and mentally god-like compared to a baseline human being, their personalities were each as flawed as those of any other mortal and they bore all the same flaws of the human character that had been seen since antiquity. During their upbringing on their respective homeworlds, the Primarchs had to learn humanity from mere humans; for almost all of the Primarchs, this resulted in their harbouring the all-too-human flaws of vanity, egotism, the hunger for power, jealousy, arrogance, insecurity and all the other sins of the human character.
As the Warmaster,Horus took over command of the Great Crusade, and took up his new duties with earnest dedication. However, there was much dissension in the ranks of the Primarchs and other parties in the Imperium over the Emperor's decision to withdraw from the campaign and return to Terra as well as to reorganise the administration of the Imperium. Only a handful of the Primarchs, among them a scheming Lorgar, remained steadfast beside the Warmaster during this period of dissension. Horus also disagreed with many of the new decrees passed by the newly established Council of Terra, intended to shift the burden of taxation and administration onto the newly-conquered ("Imperial Compliant") worlds. Even worse, Horus came to believe in his heart that he was failing his father, and was deeply wounded that the Emperor had revealed to none of the Primarchs, not even his most favoured son, why he had secluded himself upon Terra and the truth behind his secret Webway Project. These seeds of bitterness, resentment and frustration grew, and would soon bear deadly fruit...

Meanwhile, the Emperor of Mankind was on Terra organizing the infrastructure for his Imperium to function and flourish as it reached its height. The Emperor had created the Council of Terra after the Ullanor Crusade, a body of powerful civilian bureaucrats and nobles that would implement and administer the new galaxy-wide tax of resources and manpower called the Imperial Tithe and other matters of day-to-day law in the Imperium of Man while the Emperor focused on bringing his Webway Project to fruition using the technology of the Golden Throne.

The news of the creation of the Council of Terra and the new bureaucratic edicts angered some of the Primarchs still further. They did not understand why they, the Emperor's greatest champions, who had spilled their blood on a thousand worlds to re-unify all the races of Mankind, did not have seats on this new Imperial ruling body. The brotherhood of the Primarchs was being shattered bit by bit by this growing resentment and jealousy. Old arguments and differences came to the fore. Horus became ever more distant from the Emperor, seeking only glory for himself and his Luna Wolves Legion.

It was on the moon of the world of Davin that Horus' fate was sealed. This was the second time his Legion had been posted to this world; after the previous visit sixty years earlier the Luna Wolves had adopted the native Davinite institution of warrior lodges. Though these lodges had begun as simple fraternities of warriors, their secretive nature handed Lorgar, the Primarch of the Word Bearers Legion, and his First Chaplain Erebus, the tool they needed to manipulate Horus towards the service of the Chaos Gods.

Lorgar and his Word Bearers originally came from Colchis, a world of religious fanaticism. They had long worshiped the Emperor as a god. The Word Bearers had sought to spread their Cult of the Emperor to every world they added to the Imperium. But the Emperor deeply disliked and mistrusted organized religion (ironic, since he had often been the focus for much of it in his various guises across history), blaming it for much of the darkness that had plagued humanity's history. The Emperor openly and publicly refuted his alleged divinity and banned religious worship in his empire, and demanded that his subjects accept the "Imperial Truth"-- that science, reason and logic alone presented the tools required to create a better human future than any civilization had managed in the past. Lorgar did not suffer the Emperor's reprimand or views on religion well. Angered and wounded that the Emperor would not accept his devotion and worship, Lorgar turned instead to the Ruinous Powers of the Warp - who were all too willing to accept the devotion of one of humanity's Primarchs. Before long, the Word Bearers Legion had been almost entirely corrupted by the Chaos Gods, and Lorgar and his First Chaplain Erebus were tasked by the Ruinous Powers with corrupting all of their fellow Space Marines--starting with the greatest of them all, the Warmaster Horus.

During a battle against Chaos-spawned undead on Davin's moon, which had been corrupted by the forces of the Chaos God Nurgle, Horus was poisoned by a xenos blade dedicated to Nurgle known as a Kinebrach Anathame that had been stolen from the human civilisation of the Interex by Erebus after Horus and the Luna Wolves of the 63rd Expeditionary Fleet had made a disastrous first contact with them. Erebus then gifted the weapon to the Chaos-corrupted form of the Imperial Army commander Eugen Temba who the Warmaster had left behind to govern Davin sixty years before. Temba had turned to the worship of Nurgle in the interim, being transformed into a bloated mutant and killing off most of his Imperial Army garrison in the process, transforming them into undead zombies that the Luna Wolves were forced to mow down in waves as Horus personally faced off with the mutant that had been Temba. The potent living metal of the Chaos blade wielded by the plague-infused monstrosity that was Temba left Horus with a bleeding, toxic wound in his shoulder that his Legion's Apothecaries could not heal despite all the advanced technology available to them. Seeing his chance to further the designs of Chaos, Erebus next persuaded the Luna Wolves' warrior lodge to allow a group of Davinite shamans, known as the "Serpent Lodge" - Chaos Cultists all - located on the surface of Davin at their temple called the Delphos to heal him. The Luna Wolves, besides themselves with grief and the fear that their beloved Primarch would die, agreed to the suggestion, despite its direct violation of the creeds of the Imperial Truth.

During the dark rituals that followed within the Delphos, Horus' spirit was transferred from his body into the Immaterium. There, he bore witness to a nightmare vision of the future. He saw the Imperium of Man as a repressive, violent theocracy, where the Emperor and several of his Primarchs (but not Horus) were worshiped as Gods by the masses. While this vision of the Imperial future granted by the Chaos Gods was a true one, it was ironically an outcome largely created by the Warmaster's own actions. The Chaos Gods portrayed themselves as victims of the Emperor's psychic might, and claimed that they had no real interest in the happenings of the material world. Magnus the Red, the sorcerous Primarch of the Thousand Sons Legion, had also traveled into the Warp via sorcery to try and stop Horus from turning to Chaos. Magnus explained that the Warmaster's vision was only one of many possible futures, but one that Horus alone could prevent. Horus, already jealous and resentful of the Emperor, proved all too receptive to the Ruinous Powers' false vision. The Chaos Gods' pact with Horus was simple: "Give us the Emperor and we will give you the galaxy". Driven by his jealousy, desire for power and anger at what he saw as his father's abandonment of him, Horus accepted the Ruinous Powers' offer. They healed his grievous wound and filled him with the powers of the Warp. Renouncing his oath to the Emperor, Horus led his Legion, renamed the Sons of Horus, into worship of the myriad Chaos Gods in the form of Chaos Undivided. He then sought to turn many of his fellow Primarchs to the service of Chaos, and succeeded with Angron of the World Eaters, Fulgrim of the Emperor's Children and Mortarion of the Death Guard, who were the first of many to follow, along with many regiments of the Imperial Army and several Titan Legions of the Adeptus Mechanicus.

Magnus the Red, the Primarch of the Thousand Sons Legion, foresaw Horus' actions through his Legion's own use of forbidden psychic sorcery. Magnus then attempted to forewarn the Emperor of the impending betrayal of his favorite son. However, knowing that he would have to find a means of quickly warning the Emperor, and as an act of both desperation and vindication, Magnus used sorcery to send his message to the Emperor. The message penetrated the potent psychic defences of the Imperial Palace on Terra, shattering all the psychic wards the Emperor had placed on the Palace - including those within his secret project in the Imperial Dungeons, the creation of a Warp Gate to enter and turn the Eldar's Webway to the use of humanity. It was this project that the Emperor had returned to Terra to complete, leaving his Primarchs to complete the Great Crusade alone. Refusing to believe that Horus, his most beloved and trusted son would actually betray him, the Emperor instead mistakenly perceived the traitor to the Imperium to be Magnus and his Thousand Sons Legion, who had long suffered from a near-debilitating run of mutations because of the instability of Magnus' own genome. The Emperor ordered the Primarch Leman Russ, Magnus' greatest rival, to mobilize his Space Wolves Legion and take Magnus into custody to be returned to Terra for the Emperor's judgment; however,while the Space Wolves were en route to the Thousand Sons' homeworld of Prospero, Horus convinced Russ that Magnus was a traitor and needed to be destroyed rather than returned for judgment.

The Istvaan Massacres

Published materials are inconsistent on their spelling of "Isstvan": the more recently published material uses "Isstvan", while other (generally older) materials use "Istvaan". No explanation for this difference has been provided. For the sake of expediency, this article will use the spelling Istvaan, with no claims made to the accuracy of the spelling.
Preparations and Allegiances
Much of Horus' later success arose from the thorough groundwork he had laid before the opening shots of the Heresy were fired at Istvaan III. He had already swayed the Primarchs Angron and Mortarion, of the World Eaters and Death Guard Legions, respectively, to the side of Chaos because of their own various personal grudges against the Emperor. Fulgrim of the Emperor's Children had been lured to the side of the Warmaster by the promise of power and personal perfection that the Chaos Gods, especially Slaanesh, offered to him and his vain Legion. Lorgar of the Word Bearers, who had been responsible for the budding rebellion and Horus' own corruption by Chaos, was also with the Warmaster. Three of the most loyal Legions who could not be swayed to the side of Chaos, the Dark Angels, Blood Angels and Ultramarines and their Primarchs, were sent on missions by the Warmaster far from Terra and the Istvaan System. The Imperial Fists and White Scars were too close to Terra to be contacted without raising suspicion, though Horus believed - mistakenly - that the White Scars' Primarch, Jaghatai Khan, would ultimately take his side. Shortly before the Dropsite Massacre on Istvaan V, Fulgrim also attempted to sway his friend Ferrus Manus of the Iron Hands Legion to Horus' cause by using many of the same inducements that had been offered to the Adeptus Mechanicus, with whom the Iron Hands were closely allied in both temperament and philosophy. This attempt failed, and Fulgrim barely escaped with his life. Angered by the rebuff, Fulgrim promised he would deliver Manus' severed head to Horus in recompense, a promise he kept on Istvaan V. The Blood Angels were sent to the daemon-infested Signis Cluster and the Ultramarines to Calth, where a large Word Bearers force, under First Captain Kor Phaeron, had massed to hold Roboute Guilliman's massive Legion in place while Horus made his play for Terra.
Of the other eventual Traitor Primarchs, Konrad Curze, the Night Haunter, was due to face disciplinary action from the Emperor which he did not believe he deserved; the Alpha Legion Primarch Alpharius had always been closer personally to his brother Horus than his father the Emperor, although some evidence indicates that he and his twin brother Omegon's turn to Chaos was driven by their mistaken loyalty to what the Emperor would have wanted; and the Iron Warriors' Primarch Perturabo's personal bitterness towards and open rivalry with Rogal Dorn of the Imperial Fists made him an easy target for corruption.

The Thousand Sons had never planned to join Horus, but the path Tzeentch had mapped for the Thousand Sons and their potent psychic Primarch Magnus the Red ultimately led them to Chaos regardless. The Emperor had ordered Leman Russ and his Space Wolves, accompanied by the witchhunters known as the Sisters of Silence, to travel to the Thousand Sons' homeworld of Prospero and bring the one-eyed Primarch back to Terra to stand trial for violating the Council of Nikaea's prohibitions against the use of sorcery within the Imperium. While en route to Prospero, Horus convinced Russ, who had always been repelled by Magnus' reliance on psychic powers, to assault Prospero instead even though Magnus had been entirely willing to face the Emperor's judgment once he realized he was in fact being manipulated by the entities that called the Immaterium home. Unfortunately, the Space Wolves' assault on Prospero resulted in the destruction of the libraries of precious knowledge that Magnus and his fellow Thousand Sons held so dear. Mortally wounded by Leman Russ, Magnus fell to tempation as he watched Prospero and its famed libraries burn and he called out to the Chaos God Tzeentch to save both himself and the remains of his Legion. The God of Sorcery was only too happy to oblige and he transported Magnus and the Thousand Sons through the Warp to the Daemon World later known as the Planet of the Sorcerers. Magnus became a Daemon Prince of Tzeentch and now desired only vengeance against the Emperor for what he saw as a betrayal, never realizing that it was Horus who had truly engineered his downfall and corruption.

The remaining Space Marine Legions - the Raven Guard, Salamanders, Iron Hands and Space Wolves - remained staunchly loyal to the Emperor, though all but the Space Wolves would pay dearly for it in the battles to come. Beyond the Legions, Horus had already swayed Magos Regulus of the Adeptus Mechanicus to his side with promises of the Standard Template Construct (STC) databases of ancient technology recovered during the war with the Auretian Technocracy. This alliance delivered crucial Adeptus Mechanicus and Titan support to the Warmaster's Traitor Legion and Traitor Imperial Army forces.

Meanwhile, Horus and his confidante and mentor in the ways of Chaos, the Word Bearers' First Chaplain Erebus, conducted a ritual designed to communicate with the Chaotic entities of the Warp. They established contact with a daemon called Sarr'kell, who acted as an emissary of the Chaos Gods to Horus and the Traitor Legions. Horus was then deceived by the daemon into believing that the Chaos Gods had no interest in dominating the material universe, and were only lending their support so that Horus could overthrow the Emperor, who they claimed was creating devices that could destroy the daemonic beings of the Immaterium. Horus agreed, and promised to swear loyalty to Chaos Undivided after his fateful operations on Istvaan III.

The Battle of Istvaan III
The first open sign that the Warmaster Horus and his Sons of Horus Legion had turned to Chaos was made evident when Horus virus-bombed the rebellious Imperial world of Istvaan III, killing both the rebel population and the Loyalist Space Marines whom he and the other Traitor Primarchs knew would not support a rebellion against the Emperor among the Sons of Horus, World Eaters, Emperor's Children and Death Guard Legions. Unknown to the Emperor, the Word Bearers Legion had been devoted to Chaos Undivided for some time before this event. The Imperial Planetary Governor of Istvaan III, Vardus Praal, had been corrupted by the Chaos God Slaanesh whose cultists had long been active on the world, declared his independence from the Imperium, and practiced forbidden sorcery, so the Council of Terra charged Horus with the retaking of that world, primarily its capital, the Choral City. This order merely furthered Horus' plans to overthrow the Emperor. Although the four Legions under his direct command--the Sons of Horus, the World Eaters, the Death Guard and the Emperor's Children--had already turned Traitor and now pledged themselves to Chaos, there were still some Loyalist elements within each of these Legions (approximately one-third of each force); many of these warriors were Terran-born Space Marines who had been directly recruited into the Astartes Legions by the Emperor himself before being reunited with their Primarchs during the Great Crusade. Horus, under the guise of putting down the rebellion against Imperial Compliance on the world of Istvaan III, amassed his troops in the Istvaan System.
Horus had a plan by which he would destroy all the remaining Loyalist elements of the Legions under his command. After a lengthy bombardment of Istvaan III, Horus dispatched all of the known Loyalist Marines down to the planet, with the pretense of bringing it back into the Imperium. At the moment of victory and the capture of Choral City, the planetary capital of Istvaan III, these Marines were betrayed when the virus bombs began to fall on the world, launched by the Warmaster's fleet. Captain Saul Tarvitz of the Emperor's Children, however, was aboard the Emperor's Children flagship Andronius and discovered the plot to wipe out the Loyalist Marines of the Traitor Legions. He was able, with help from Battle-Captain Nathaniel Garro of the Death Guard who was in command of the Death Guard frigate Eisenstein, to reach the surface of Istvaan III despite pursuit and warn the Loyalist Space Marines he could find of all four Legions of their impending doom. Those that heard the warning took shelter before the virus bombs struck. The civilian population of Istvaan III received no such protection: Twelve billion people died almost at once as the lethal flesh-dissolving virus carried by the bombs infected every living thing on the planet. The psychic shock of so many deaths at one time shrieked through the Warp, briefly obscuring even the Astronomican. The Primarch of the World Eaters, Angron, realising that the virus bombs had not been fully effective at eliminating all the Loyalists, flew into a rage and hurled himself at the planet with 50 companies of Traitor Marines. Discarding tactics and strategy, the World Eaters Legion's Traitors worked themselves into a frenzy of mindless butchery. Horus was furious with Angron for delaying his plans, but the Warmaster sought to turn the delay into a victory and was obliged to reinforce Angron with troops from the Sons of Horus, the Death Guard, and the Emperor's Children. Fortunately, a contingent of Loyalists led by Battle-Captain Nathaniel Garro of the Death Guard escaped Istvaan III aboard the damaged Imperial frigate Eisenstein and fled to Terra to warn the Emperor that Horus had turned Traitor.

On Istvaan III, the remaining Loyalists, under the command of Captains Tarvitz, Loken and Tarik Torgaddon, another Loyalist Son of Horus, fought bravely against their own traitorous brethren. Yet, despite some early successes that delayed Horus' plans for three full months while the battle on Istvaan III played out, their cause was ultimately doomed by their lack of air and Titan support. During the battle the Sons of Horus Captains Ezekyle Abaddon and Horus Aximand were sent to confront their former Mournival brothers, Loken and Torgaddon. Horus Aximand beheaded Tarik Torgaddon, but Abaddon failed to kill Loken when the building they were in collapsed. Loken survived and witnessed the final orbital bombardment of Istvaan III that ended the Loyalists' desperate defence. To prove his worth and loyalty to Lord Commander Eidolon of the Emperor's Children - and thusly to his Primarch, Fulgrim - Captain Lucius of the 13th Company of the Emperor's Children, the future Champion of Slaanesh known as Lucius the Eternal, turned against the Loyalists within his Legion that he had fought beside because of his prior friendship with Saul Tarvitz, slaying them personally, an act for which he was then accepted back into the Emperor's Children on the side of the Traitors. In the end, the Loyalists retreated to their last bastion of defense, only a few hundred of their number remaining. Finally, tired of the conflict, Horus ordered his men to withdraw, and then had the remains of the Choral City bombarded into dust for a final time from orbit.

Flight of the Eisenstein
The seventy Loyalists of the Death Guard Legion and the Imperial Saint Euphrati Keeler led by Battle-Captain Nathaniel Garro commandeered the Imperial frigate Eisenstein and, evading the Traitor forces of Horus, were able to escape from the Istvaan System into the Immaterium, after being told what was happening. The Eisenstein was badly damaged by the Death Guard battleship Terminus Est during its escape from Istvaan III and it was assaulted by undead minions (possibly including the first known Plague Marines) of Nurgle while it was within the Immaterium, forcing it to make a crash emergence from the Warp; the repeated traumas left all of the frigate's astropaths dead, and its lone Navigator was mortally wounded. However, Garro managed to attract the attention of passing Loyalist starships by setting the vessel's Warp-Drives to self-destruct and ejecting them from the starship. Rogal Dorn's Imperial Fists Legion's massive mobile fortress-monastery Phalanx and the Legion's fleet had been becalmed in the Warp with its fleet for some time due to the waxing power of the Ruinous Powers as the Heresy began, and his Navigators had sensed the detonation of the Eisenstein's Warp-Drives. Making an immediate course for the location of the detonation, Dorn met with Garro, who explained to him all that had happened with the Traitor Legions. Dorn was reluctant to believe Garro's tale, but overwhelming proof from a Remembrancer (journalist) named Mersadie Oliton who had escaped from Horus' flagship, the Vengeful Spirit, and Garro's dogged insistence convinced the Primarch, and the Phalanx fortress set a course for Terra.
The fate of the Eisenstein's survivors is unknown. Sequestered on Luna in a tower belonging to the Sisters of Silence after their arrival in-system, Garro, the rest of his Loyalist Death Guard, Captain Iacton Qruze of the Luna Wolves, and the warriors of the Silent Sisterhood faced one of the Death Guard Marines named Solun Decius who had succumbed to the temptations of the Chaos God Nurgle after being infected with one of the Lord of Plague's more virulent illnesses now known as Nurgle's Rot by the undead minions Nurgle had unleashed on the Eisenstein. Seeking to end his pain Decius allowed himself to become possessed by a Lesser Daemon of Nurgle, a variant Plaguebearer called the Lord of the Flies. Afterwards, Garro and Captain Qruze were met by Malcador the Sigillite, leader of the Council of Terra and the Emperor's Regent, who informed them that the Emperor had need of people who were strong of will and as "inquisitive" as they. These Loyalist Space Marines of the Traitor Legions are thought to be the founding members of the Imperial Inquisition and the militant arm of its daemon-hunting Ordo Malleus - the Grey Knights.

The Drop Site Massacre on Istvaan V
In response to Horus' betrayal at Istvaan III, the Primarch of the Imperial Fists Legion, Rogal Dorn, on the direction of the Emperor who had learned of Horus' actions from the Loyalist survivors aboard the Eisenstein, ordered seven Loyalist Space Marine Legions to Horus' base on the world of Istvaan V to challenge the Warmaster. They would attack in two waves and fall under the supreme command of the Iron Hands' Primarch Ferrus Manus. The Legions comprising the first wave were the Iron Hands, Salamanders, and Raven Guard. The Legions comprising the second wave were the Alpha Legion, Night Lords, Iron Warriors, and a large contingent of Word Bearers that their Primarch Lorgar had stationed in the star system. Unknown to Dorn and Ferrus Manus, the Night Lords, Alpha Legion, Iron Warriors and Word Bearers had all turned from their service to the Emperor and pledged their loyalty to Horus, and been instructed to keep their new allegiance to Chaos a secret.
The Iron Hands, Salamanders and Raven Guard were deployed in the first wave of the assault. After they secured the drop site, they were to have been followed by the arrival of the other four Legions. The first wave secured the drop site at heavy cost. Horus ordered his front line troops to fall back, tempting Ferrus Manus to overstretch his already thin lines. Against the advice of Corax and Vulkan, Manus led his Veterans against the fleeing Traitor Marines unsupported. Manus then brought his brother Fulgrim to combat. As the two Primarchs drew their weapons, the Raven Guard and Salamanders fell back to regroup and allow the second wave's Legions to advance and earn glory. However, as they returned they were mowed down by the four Traitor Legions that had landed to supposedly support them, thus revealing their new allegiance to Chaos. Horus then pressed his own attack and sandwiched the Loyalists between the two Traitor forces, killing most of them. Several determined groups of Loyalist Space Marines managed to break out of the trap and escape back to the few remaining Loyalist drop ships.

Ferrus Manus was beheaded in the battle by Fulgrim. Fulgrim was beset by grief as he stared down at his once beloved brother's headless body; in this moment of weakness as the Emperor's Children Primarch repudiated his allegiance to Chaos, the Greater Daemon of Slaanesh within his potent blade tricked him into lowering his mental shields, and possessed him, crushing Fulgrim's soul into the recesses of his mind, a mute witness to the daemon's actions. The daemon would present Ferrus Manus' head to a delighted Horus.

Barely a handful of Loyalist Space Marines escaped with their lives from Istvaan V to bring word of the further betrayal of four more Astartes Legions to the Emperor. A critically wounded Corax was brought back to Terra in a stasis tube. Vulkan was missing, presumed dead, though he would later reemerge after a harrowing journey back to Terra to lead his Legion once more. Vulkan was one of the Primarchs who protested Roboute Guilliman's publication of the Codex Astartes and the splitting of the remaining Space Marine Legions into 1,000-man Chapters following the death of Horus and the end of the Horus Heresy.

The Route to Terra

After the Drop Site Massacre conducted against the three Loyalist Space Marine Legions of the Salamanders, the Iron Hands and the Raven Guard by the Traitor Legions loyal to the Warmaster Horus on the world of Istvaan V, it became clear that eight of the eighteen Space Marine Legions had turned to Chaos and against the Emperor of Mankind. Horus openly and publicly declared that he would no longer follow the Emperor, believing him to be undeserving of the battles fought in his name, and the Warmaster took over the formal leadership of the Traitor Legions as their new overlord, supported by elements of the Imperial Army, a portion of the Adeptus Mechanicus and the Titan Legions that had chosen to serve Chaos known as the Dark Mechanicus, strong Imperial naval forces then still part of the Legiones Astartes' Great Crusade Expeditionary Fleets, and the daemon-spawn of Chaos.
Over the next several years, the combined Traitor fleets spread across the galaxy, unleashing a brutal civil war upon many of the planets that they had once helped to bring into the Imperium in the first place. Secretly guided by the Ruinous Powers, the Traitor Legions and their related support forces no longer worried about the rules of war, civilian casualties or proportionality; it was a common tactic of the Traitor fleets to simply unleash a total orbital thermonuclear bombardment upon a single inhabited world in a heavily defended Imperial star system to induce all of the other worlds and orbital installations to surrender. Casual brutality and even genocide became the norm for the Traitors as they fell ever more deeply under the control of Chaos. Slowly but methodically, Horus and the Traitor Legions forged a path across the galaxy lit by the burning nuclear pyres of countless worlds. Those planets spared the destruction faced an even worse fate: occupation and control by the Chaos-corrupted Traitor forces, who took great pleasure in unleashing the perversions of the Dark Powers upon the captive populaces. Many prayed to the Emperor for release from their torments, and the strength of the Lectitio Divinitatus cult that believed in the Emperor's divinity only began to grow as the nightmare of civil war scourged the Imperium of Man.

The aim of the Traitor Legions' destructive interstellar advance soon became clear: their goal was the conquest of Terra, the heart of the Imperium of Man, so that Horus could fulfill his promise to the Chaos Gods and throw down the Emperor of Mankind, their greatest enemy. The Sons of Horus, the Death Guard, the Emperor's Children, the World Eaters, and elements of the Word Bearers prepared to rendezvous at Mars. The rest of the Word Bearers Legion was tasked with destroying Roboute Guilliman and his Ultramarines on the world of Calth in the Eastern Fringes of the galaxy.

The Imperial Fists Legion's Primarch Rogal Dorn and the Regent of the Imperium, Malcador the Sigillite, receiving the few survivors from the Dropsite Massacre of Istvaan V as they retreated back to Terra, became aware of the full implications of their position and the strength of Horus and the Traitor forces. Rogal Dorn immediately recalled all Loyalist Imperial forces back to Terra in preparation for Horus' invasion. Of the Space Marine Legions still loyal to the Emperor, the Space Wolves had just completed the Burning of Prospero, the Thousand Sons Traitor Legion's homeworld near the Chondax System, where the White Scars were stationed. Without warning, the Alpha Legion's fleet broke from the Warp and engaged the Space Wolves forces of the Primarch Leman Russ, hammering his smaller fleet and forcing Russ to resort to hit-and-run attacks. The Alpha Legion's Primarch Alpharius also attacked the nearby forces of the White Scars piecemeal in an attempt to draw that larger Astartes Legion into conflict.

The White Scars' Primarch Jagahatai Khan wished desperately to aid Russ, yet as the Traitor Legions' starships attacked, he received the astropathic order from Rogal Dorn. Khan was to bring his Legion back to Terra, immediately. Dorn also commanded him to relay the order to Russ and add that should he succeed in evading his attackers, only then should he attempt to head for Terra. Relaying the message and adding his apology for his inability to aid the Space Wolves, the White Scars made for Terra. Russ resolved to meet the Alpha Legion with renewed determination. With help from an unlikely quarter, the Space Wolves would eventually turn the tables on their attackers and make the Warp jump to Terra, well after the siege on the Imperial Palace had begun.

Similarly at the world of Calth, the Ultramarines expeditionary force, battered by the relentless attacks of the Word Bearers, had dug in on the planet's surface, while Primarch Roboute Guilliman and the remnants of his Ultramarines' fleet began to organise hit-and-run attacks. Surveying the scene on the planet, Guilliman rapidly assessed his ground troops' positions, and began broadcasting orders to his men, co-ordinating each pocket of defence. One such pocket, under Brother-Captain Ventanus, organised a breakout, and retook Calth's defence cannons and laser silos, reaping a great tally of Traitor starships. Ventanus' victory evened the odds in space, buying time for the vast remainder of the Ultramarines Legion to arrive at Calth and drive the Traitors away. Reunited as a single force, the Ultramarines received Malcador's orders and set out for Terra, moving through the Warp as rapidly as they could even as they realised that they would probably arrive too late to make a difference.

As this happened, the Night Lords arrived in the Eastern Fringe of the galaxy to engage the Dark Angels, and the Iron Warriors' armada broke from the Warp to engage the Imperial Fists' fleet marooned near the Chaos Space Marines' headquarters world of Istvaan V. Surviving the initial thrust of the Iron Warriors' attacks, the Imperial Fists' armada held fast and scattered the Primarch Perturabo's fleet, then made their own Warp jump to Terra in a desperate race against time.

Meanwhile, in the Signis Cluster, the Blood Angels, granted new and terrible power by a mysterious mass rage (that would resurface again during the Siege of Terra) had triumphed, smashed the hordes of the Chaos daemons asunder and were able to make the Warp jump to Terra.

As the Warmaster was heading towards Terra he received an unexpected communication from the recently betrayed Thousand Sons Primarch Magnus the Red. The Space Wolves had driven the Thousand Sons from their homeworld of Prospero after being manipulated by Horus into attacking the Thousand Sons homeworld instead of simply taking Magnus into custody to return him peacefully to terra to face charges of the illegal use of sorcery by the Emperor. Devastated by the Space Wolves' destruction of his Legion's precious storehouses of knowledge about the Immaterium and sorcery, and having turned to the Chaos God Tzeentch to save himself and his Astartes Legion, Magnus pledged his allegiance and the allegiance of the Thousand Sons Legion to Horus and Chaos in retaliation against the Emperor for this betrayal. The Thousand Sons were en route to Terra where they would link up with Horus' forces.

Of the nine remaining Loyalist Space Marines Legions, only the White Scars and the Blood Angels were able to join Rogal Dorn and his Imperial Fists in the defence of Terra before the arrival of the Traitor Legions in the Solar System. Three entire Titan Legions of the Adeptus Mechanicus and close to two million soldiers of the Imperial Army stood alongside them to face the Traitors in a battle that would determine the fate of Mankind for 10,000 years.

Siege of the Imperial Palace

The Landing on Terra
The siege of Terra by the Traitor forces of Horus began with an orbital bombardment by the Warmaster's fleet as the prelude to invasion. Although the Loyalist fleets and defenders fought back and the massive orbital defences on Luna reaped more than a quarter of the starships in the Traitor fleet they, like the Loyalist soldiers on the surface, were too few to face the combined forces of so many Traitor Legions, and were mowed down without mercy. After days of bombardment, the Chaos Space Marines landed on the surface of Terra in Drop Pods and advanced on the two spaceports nearest the location of the Imperial Palace to secure them in preparation for the main landings of the Traitor forces. Elements from five of the Traitor Legions participated in the battle, aided by the Traitor forces already on the surface. Despite the brave efforts of the Loyalists, the Eternity Wall and the Lion's Gate Spaceports fell within hours to the Forces of Chaos. Dark Chaos Cultists made their invocations, calling down the Greater Daemons of Chaos from the Warp directly onto Terran soil. With the spaceports secured, Horus' remaining troops of the Traitor Legions and their Traitor Imperial Army and Dark Mechanicus support forces landed en masse, and the hulking transports carried thousands of troops each as well as bringing to the battlefield the terrible Traitor Titans that served the Warmaster's cause and had been infected with the daemonic forces of Chaos. The transports' immense size made them prime targets for Terra's defence lasers. Although many of the Traitor landing craft were destroyed in-atmosphere, many more made it to the surface, disgorging yet more soldiers, main battle tanks and Traitor Titans to add to the besiegers' strength. They met stiff resistance from the Loyalists as the Imperial defenders knew that the survival of their homeworld, their Emperor, and the entirety of the human race rested on their shoulders.
The Siege
The Chaos besiegers forced the Imperial defenders back to the walls of the Imperial Palace, where thousands died slowing the assault. The Primarch Angron of the World Eaters Legion, now a Daemon Prince of the Blood God Khorne, came forth before the walls of the Palace and demanded the Loyalists' surrender, saying that they were cut off, outnumbered, and defended a ruler unworthy of their loyalty. Many would have surrendered to Angron after seeing the sheer power of the Forces of Chaos that stood arrayed before them had it not been for the Primarch Sanguinius, the winged and seemingly angelic leader of the Blood Angels Legion. The two Primarchs, once brothers, gazed at each other, perhaps communicating telepathically. Eventually Angron withdrew from before the gates of the Imperial Palace, telling his forces, not without some relish at the prospect of slaughter, that there would be no surrender.
The siege of the Imperial Palace then began in earnest. Three times the Forces of Chaos scaled the walls, and three times were hurled back by Sanguinius and his Blood Angels. Outside the Palace walls, Space Marine and Imperial Army forces led by Jaghatai Khan, the Primarch of the White Scars Legion, unsuccessfully tried to draw the bulk of the besiegers' army away from the Palace. Soon the outnumbered defenders were pushed back into the maze of corridors and bulwarks within the Palace walls. Frustrated with his army's slow progress, Horus ordered the Legio Mortis (Death's Head Legion), a Traitor Titan Legion, to demolish entire sections of the wall. Despite grievous losses, the Titans, led by the infamous Imperator-class Battle Titan Dies Irae, gouged open breaches in the Imperial Palace's defenses, which the Traitors then flooded through.

Facing a breach and potential collapse of the Imperial defences, Jaghatai Khan decided on a change of plan. Rather than assaulting the almost-invincible flanks of the Chaos army, Khan redirected his highly mobile White Scars Space Marines and the surviving Loyalist Tank Divisions of the Imperial Army to Lion's Gate Spaceport. At dawn Jaghatai's lightning raid caught the Traitor garrison at the spaceport completely by surprise, and reclaimed the spaceport for the Imperium. The Khan ordered his troops to reactivate the spaceport's defence lasers to prevent the Traitor fleet from bringing down any more troops and equipment and form a defensive perimeter to hold their newly reconquered territory. Khan's troops repelled several frenzied counter-attacks from the Traitors, and began firing on Horus' unprotected dropships. The Khan's plan worked perfectly: the flow of the Traitors' men and machines to the Imperial Palace had been cut in half at a single stroke. Inspired by this success, the Loyalists also tried to seize back the Eternity Wall Spaceport, but were driven back by the Chaos forces without difficulty, as they had reinforced their garrison following the loss of the Lion's Gate .

Inside the Palace, the defenders had been forced back to the Eternity Gate, the sole point of entry into the inner sanctum of the Imperial Palace. The Blood Angels and Imperial Fists Space Marines tried to hold back the attacking Chaos troops, while the remaining Loyalists made it through the Gate. Soon the mighty Bloodthirster Greater Daemon Ka'bandah came forth and bellowed out a challenge to Sanguinius in the name of his master Khorne. The daemon hurled itself at the Angel of Baal, barely allowing him time to parry the daemon's strikes. The two took to the air, trading blows and battle cries high above the heads of the two forces. Already fatigued from the siege, Sanguinius was cast down by the daemon, pulverising the concrete below upon impact. The Loyalist forces seemed to collectively groan.

Yet the Blood Angels' Primarch was not beaten, only stunned by the force of the impact. Sanguinius cleared his head, forced himself back to his feet, and once again took to the sky. The Angel seized the gloating daemon, holding it by the right ankle and arm. The Primarch hefted the creature high and broke its back over his knee, before hurling the daemon's carcass back at the besiegers, who howled in despair as the last Loyalists fell back and made it into the Imperial Palace's inner sanvtum before the great portal of the Eternity Gate was shut tight behind them. Of course, as a daemon, Ka'bandah could not truly be slain, only banished to the Warp for a 1000 standard years, but the Bloodthirster's spirit was sent howling back into the Immaterium to meet the displeasure of his master the Blood God.

The Eternity Gate was closed.

The Endgame
The siege of Terra following the initial assault on the Imperial Palace lasted for 55 days. Both sides knew that the defeat of the Imperium of Man was near after the defence of the Eternity Gate. Sensing this, and knowing that he must complete the siege before the arrival of Loyalist reinforcements from the other Space Marine Legions that were already on their way, Horus prepared to teleport to the surface from his flagship, the Vengeful Spirit, to lead his forces in person. Before this could happen, the Word Bearers' First Chaplain Erebus broke the news to Horus: their daemonic allies in the Warp had informed them that the Dark Angels and Space Wolves Legions were nearing Terra; and the Ultramarines were only a short distance behind.
At that moment, Horus despaired; his gamble had failed, weeks of further conflict would be needed to break the defenders and the Emperor's reinforcements would arrive in mere hours. What happened next is disputed in the Imperial historiography of the Heresy; some believe Horus disabled his void shields as he experienced one last moment of regret for his betrayal of his father and his turn to Chaos, while others believe it was a personal challenge to the Emperor. Nevertheless, Horus lowered the void shields of his flagship, the battle barge Vengeful Spirit. The lowering of these shields was detected by the Loyalist vessels in orbit and the information was relayed to the Imperial Palace.

The Emperor of Mankind rose to the challenge, leading his elite personal guard, the Adeptus Custodes, the Primarchs Sanguinius and Rogal Dorn, and several companies of Imperial Fists and Blood Angels Veteran Space Marines in the assault and teleported aboard the Vengeful Spirit. Horus used his Chaotic powers to scatter the Emperor's force throughout the massive warship when they teleported up through the Warp. Each fought a series of battles against the elite Forces of Chaos aboard the corrupted starship, attempting to link up with their comrades and confront Horus.

It was Sanguinius who reached hs brother Horus first. The Warmaster attempted to turn the Blood Angels' Primarch, his oldest and closest friend among the other Primarchs, to Chaos one last time. When Sanguinius refused to be corrupted, Horus attacked. Wounded from his many battles on Terra and the terrible battle with the daemon Ka'bandah, Sanguinius proved to be no match for Horus, now at the peak of his daemonic power after his long alliance with the Ruinous Powers. Horus strangled the Angel of Baal with ease. An alternate version of this event sometimes recorded in the Imperial records has Sanguinius cutting a small hole in the Warmaster's Power Armour before he died, as this hole aided in the Emperor's final defeat of Horus.

When the Emperor of Mankind finally entered the throne room of the Vengeful Spirit, he saw the winged corpse of the angelic Sanguinius lying at Horus' feet. Horus called the Emperor foolish for refusing the power that the Chaos Gods offered to men, and timid for not taming them to his will if he was truly the Master of Mankind as he claimed. Horus proclaimed that if the Emperor would kneel before him, then he would spare his life. But the Emperor, tens of millennia older than his misguided and once beloved son, knew well the ancient trap that had snared Horus. The Emperor told the corrupted Primarch that he was the deluded slave of Chaos, not its master, for no mortal could ever truly claim to be more than simply a pawn of the Ruinous Powers. Snarling, Horus hurled bolts of daemonic lightning at the Emperor, but the Emperor nullified them with his own immense psychic abilities. The die was cast. Each god-like being knew that the fate of humanity now hung in the balance.

The Emperor and Horus engaged one another in the throne room of the massive battle barge, a battle that was both physical and psychic in nature. Though the Emperor's psychic gifts and martial skills were unequaled, he found himself unwilling to summon his full strength against his beloved son. The Emperor suffered grievous wounds at Horus' hands, and after a score of thrusts, parries and counter-thrusts between the Emperor's Runesword and his own Lightning Claw, Horus sliced open the Emperor's chest armour, then opened his jugular and severed the tendons in his right wrist, disarming the Emperor. A psychic blast seared the flesh from the Emperor's face, destroying one of the Master of Mankind's eyes. After tearing the Emperor's right arm from its socket, Horus raised his father's broken body high over his head, and broke his back over his knee.

At that moment, a lone Adeptus Custodes warrior entered the bridge. Horus showed the Imperial bodyguard the Emperor's broken form and laughed at the Custode. The valiant Imperial warrior roared and charged the Warmaster. He was flayed alive by a glancing psychic blast from Horus. In other accounts of this final battle by some Imperial sources, an Imperial Fists Terminator attacked Horus; in still other versions, the doomed man is an Imperial Army trooper named Ollanious Pious.

The casual brutality of the Warmaster's act galvanised the Emperor as he realised what awaited Mankind under the rule of Horus and the Chaos Gods. Realising at last that his favoured son was truly lost to the corruption of Chaos, the Emperor finally gathered his full and awesome psychic power in the Immaterium and unleashed a lance of pure Warp energy that pierced the gloating Horus' psychic defenses and ripped his body apart. In some versions of the tale, this blast was only able to pierce the Warmaster's body through the hole that had been made by Sanguinius before his death. Just before Horus died, he looked his father in the eye, shedding a single tear, begging his father to forgive him for his betrayal. The Emperor saw regret in his fallen son's eyes. The Emperor also knew that the Ruinous Powers could attempt to possess Horus again, and that he would not be there to stop him if they did. Driving all of the near infinite reserves of compassion from his mind for the sake of the humanity he had served and loved all the years of his long life, the Emperor destroyed Horus utterly, his essence burned from existence in both the physical world and the Immaterium so that the Ruinous Powers could not resurrect Horus as a Daemon Prince through their claim on his soul.

The destruction of Horus' soul sent a psychic shockwave surging across the Solar System, casting the daemons of Chaos back into the Warp, and spreading mass panic among the Traitor Legions and other Traitor forces on the surface of Terra in seconds as the Chaos Gods found their powers disrupted temporarily by the death of their favoured mortal vessel. It became clear to the Forces of Chaos that their leader had been defeated. A terrible, berserk fury later known as the Black Rage had encompassed the Blood Angels at the moment of their Primarch's death, and they were surging forth to scatter the attackers. Retreat turned to rout, and rout soon turned to bloodbath; thousands upon thousands of Traitor Space Marines and Titans fell attempting to flee. The ground before the Sanctum Imperialis ran red with the blood of Traitors and heretics.

Meanwhile, the Primarch Rogal Dorn finally found his way to the corrupted starship's bridge, only to discover his fallen brother, Sanguinius, and the shattered body of the Emperor, who was now on the verge of death, his remaining psychic energy spent in the battle with Horus. It was then that the Emperor whispered instructions to Dorn, urging the Imperial Fists' Primarch to take him to the device known as the Golden Throne in the inner sanctum of the Imperial Palace. The surviving Loyalists teleported back to the Imperial dungeons beneath the Imperial Palace. Here Malcador the Sigillite, the Regent of Terra who was himself an exteremly powerful psyker, had briefly taken the Emperor's place on the Golden Throne, thus keeping the Warpgate to the Webway that the Emperor had been building for the benefit of humanity safely closed. Malcador's body collapsed to dust from the sheer strain of holding back the dangers of the Immaterium from coming through the Webway gate and assaulting Terra as he was removed from the Throne and the Emperor put in his place. Yet, before his death, the Sigillite imparted his remaining psychic energy to the Emperor to restore the Master of Mankind's consciousness for one final time so that he could deliver his final instructions to his servants before being interred in the device as the Adepts of the Adeptus Mechanicus furiously worked to modify the device to the Emperor's specifications.

The Emperor then spoke his final words to his followers. He urged them to continue the fight to free humanity from the Forces of Chaos and the machinations of the Ruinous Powers as well as the ignorance that continued to assail it. And then the Master of Mankind spoke no more, his body entombed within the life-support mechanisms of the Golden Throne, his spirit caught between the Warp and in a crippled, decaying body for millennia. Unable to complete the Webway project that the Golden Throne had originally been intended to create and maintain, the Emperor now chose to use its psychic augmentation mechanisms both to maintain his shattered body's life support functions and to project his mind into the Immaterium where he would create and maintain the Astronomicon navigation beacon to hold the Imperium together and battle the Chaos Gods on their own plane, always seeking to protect Mankind from their corruption and depredations. The Imperium of Man had survived the Horus Heresy intact, but would evolve into the bastion of repression and brutality the Emperor had long fought against without his direct, guiding hand upon it. In this, at least, the Chaos Gods had won a partial victory, for this state of affairs would ensure that their temptations would continue to corrupt the weaker members of the human race and prevent the final establishment of Order across the galaxy. Yet, for all its terrible and growing flaws over the next ten millennia, the Imperium would also offer humanity its best and perhaps only hope for survival in an uncaring and increasingly hostile universe.

The Great Scouring and the Reformation

As the flames of the civil war subsided across an Imperium in which 2.3 trillion human beings had died and countless worlds had been utterly shattered, Ultramarines Primarch Roboute Guilliman rallied the surviving Loyalists, stretching his Legions thin across the galaxy to buy time for the other Space Marine Legions to rebuild and rearm to take the fight to the remaining Chaos Space Marine Traitor Legions in what became known as the Great Scouring. Although some Traitor Legions had fled to the relative safety of the Eye of Terror, the Iron Warriors continued to hold fast to the worlds they had conquered, and were dislodged only after decades of gruelling warfare. Similarly, the Chaotic Night Lords Legion continued their spree of genocide and terror along the Eastern Fringe of the galaxy. This campaign endured until the Night Lords' Primarch Night Haunter was assassinated on the world of Tsagualsa. Shortly after, Roboute Guilliman slew the Alpha Legion's Primarch Alpharius (but not his secret twin brother Omegon) on the planet of Eskrador.
As the last of the Traitor Legions fled to the safety of the Eye of Terror at the end of the Great Scouring, Roboute Guilliman turned his attention to rebuilding the Imperium of Man itself in what became known to later Imperial historians as the Reformation. Never again would it succumb to a Heresy so vast or destructive. Guilliman divided the Imperial Army into the separate branches of the Imperial Navy and the Imperial Guard, diluting their ability to mutiny en masse by creating a bureaucratic rivalry between the services. The Imperial Inquisition was founded around this time to prevent the secret spread of the corruption of Chaos through the ranks of humanity from happening again (some sources suggest it was formed before the Horus Heresy at the instigation of the Emperor and his Regent, Malcador the Sigillite from those few Space Marines of the Traitor Legions that had remained loyal to the Emperor), and the Grey Knights Space Marines Chapter was founded to combat daemonic incursions as part of the Inquisition's Ordo Malleus. The Council of Terra that had been created by the Emperor after the Ullanor Crusade to begin to provide the Imperium with some form of civilian administration was succeeded by the High Lords of Terra: a Senatorum Imperialis composed of the 12 most powerful individuals in the Imperium who were the leaders of its various governmental institutions known collectively as the Adeptus Terra, who were to act as the regents of the Imperium and rule in the Emperor's name as they sought to carry out his will.

Of all the changes brought upon the Imperium of Man by Roboute Guilliman after the Horus Heresy, the most pivotal was the Second Founding of the Space Marines. This reform, enacted seven standard years after the defeat of Horus, saw the remaining Loyalist Space Marine Legions broken up into smaller, more flexible 1000-man units known as Chapters, thus transforming the Legiones Astartes into the Adeptus Astartes. Although Rogal Dorn, Vulkan, and Leman Russ opposed breaking up their beloved Legions, Guilliman's initiative had the backing of Corax, Jaghatai Khan and the High Lords of Terra, and the measure passed irregardless of the other Primarchs' opposition, marking the end of the Primarchs' dominance over Imperial life and the imposition of mortal rule that the Emperor had desired. The Adeptus Astartes were granted almost total autonomy from every other Imperial organisation, including the Inquisition, but not from the High Lords of Terra who spoke for the Emperor. Never again would one man wield the power of an entire Space Marine Legion or have such total control over the Imperium. At the same time, Roboute Guilliman wrote the Codex Astartes, the famed tome that laid out the proper organisation, tactics and order of battle for a Space Marine Chapter. The Codex soon became a sacred tome for the Ultramarines and their myriad Successor Chapters, the backbone of the Adeptus Astartes in the centuries after the Horus Heresy. Other Chapters, like the Blood Angels, the Dark Angels and the Space Wolves, adopted the Codex's guidelines only in part or not at all, a sign of their continuing disagreement, however ineffective, with the reforms of Roboute Guilliman.

[Piksi]

The Age of Rebirth c. M31-c. M 32

During the Age of Rebirth the Imperium of Man slowly recovered from the Horus Heresy.The myriad wars of the Great Scouring were fought in the decades immediately after the end of the Horus Heresy and the death of the Warmaster. In a lengthy campaign, the Imperium's forces hunted and banished the remaining Traitor Marine Legions from human space. Eventually the Chaos Space Marines and the Ruinous Powers' other followers among the Forces of Chaos found refuge in the massive Warp rift known as the Eye of Terror. For a time the Imperium knew peace from the corrupted followers of the Chaos Gods. At the same time, many alien races that had been fought during the Great Crusade reappeared in human space to take advantage of the disruptions caused by the Horus Heresy and plagued the vulnerable worlds of Man. In order to prevent a single person from controlling as much military power as Horus had mastered and eliminate the risk of another large-scale civil war, numerous reforms were enacted to reshape the Imperium's political and military structure. The Imperial Army was divided into the land-based forces of the Imperial Guard, and the space-based forces of the Imperial Navy, each with a separate chain-of-command structure and bureaucracy. The remaining nine Loyalist Space Marine Legions adopted the Codex Astartes written by the Ultramarines' Primarch Roboute Guilliman and were split into the many smaller Space Marine Chapters of the Second Founding that were comprised of only 1,000 men each along with their own supporting spacecraft and planetary fiefdoms.
The byzantine politics of the Imperium took a calamitous turn in 546.M32 when the High Lords of Terra, the successors of the Council of Terra that had been established to administer the day-to-days affairs of the Imperium and now ruled in the Emperor's name were slain to a man on the orders of Drakan Vangorich, the Grand Master of the Officio Assassinorum. A Space Marine retribution force drawn from the Halo Brethren, Imperial Fists and Sable Swords Chapters tracked the Grand Master to an Assassinourm temple. The commander of the Astartes strike force was assassinated as soon as he made planetfall, but the remaining Battle-Brothers carried out the attack without him. Inside the temple they were attacked by 100 Eversor Assassins. Only a single Space Marine survived to reach the Grand Master and end his life with a boltgun. The Imperium descended into anarchy for several years as new High Lords rose to power.

The Forging (c. M32 - c. M35)

The Forging is also sometimes known to Imperial historians as the Golden Age of the Imperium. During this period the Adeptus Terra brought the most important human-settled star systems of the galaxy that had not been reached by the Great Crusade under Imperial control and expanded the interstellar borders of the Imperium. Internal stability was gained with the establishment of Astropath Choirs on countless worlds, which allowed a reliable network of interstellar superluminal communication to function using the power of an Astropath's telepathy to send and receive mesages across light years. This period also saw the slowing of the decline in the Imperium's technology and the growth of the interstellar economy due to the rediscovery of a valuable Standard Template Construct (STC) database from the Dark Age of Technology in the Cana System as the Imperium expanded. Once more the Imperium repelled the forces of Chaos renegades, heretics and aliens alike across the galaxy and reclaimed countless lost and rebellious regions for the human race.
In 265.M33 Admiral Usurs of the Imperial Navy was cast down by the High Lords of Terra for becoming too ambitious. However, he is still too powerful within the Navy to be executed without intiating a costly civil war, so he is instead dispatched on an Explorator mission to the intergalactic gulf beyond the Milky Way. For the following decade, Usurs' reports reach Terra by Astropath, detailing the conquest of new star systems for the Emperor. After two decades, these reports finally cease. Contact is never reestablished with the star systems Usurs mentioned in his reports.

In 401.M34 the terrible event known as the Howling unfolded. Black Templar Space Marines ended the Catelexis Heresy by executing the Cacodominus, an alien cybernetic psyker whose formidable powers allowed it to psychically control the populace of thirteen hundred star systems! Unfortunately, the Cacodominus' death scream was amplified by the Warp and burned out the minds of a billion human Astropaths as well as distorting the beacon of the Astronomicon. Millions of starships were lost in the resulting upheaval and entire sub-sectors of the Imperium slid into barbarism without the dictats of the Administratum to guide them.

The Nova Terra Interregnum (c. M35)

The Nova Terra Interregnum is also known as the Time of the Twin Empires and it lasted for 900 standard years during the 35th Millennium. During this period the rebellious Ur-Council of Nova Terra dismissed the authority of the High Lords of Terra and claimed separate rule over the Imperium's Segmentum Pacificus. After almost a millennium of low-grade civil war and political maneuvering, the Cataclysm of Souls in 975.M35 reunited the Imperium. In that year the Ecclesiarchy tried to transform the Imperium into a theocracy and usurp the power of the rest of the High Lords of Terra. Their efforts ended only in stirring up massive religious civil wars against the Ur-Council who were denounced as heretics who stood in defiance of the will of the God-Emperor when they rejected the Ecclesiarchy's attempts to increase its power over the state. This religious rebellion on many worlds of the Segmentum Pacificus ultimately overthrew the Ur-Council and restored the rule of the High Lords over the entirety of the Imperium's territory, though the power of the Ecclesiarchy had been increased throughout the Imperium as a result.

The Age of Apostasy (M36)

The Age of Apostasy is renowned for the Reign of Blood, the time of High Lord Goge Vandire's rule as both Ecclesiarch of the Adeptus Ministorum and Master of the Adeptus Administratum. Vandire plunged the Imperium into a civil war nearly as damaging as the Horus Heresy between his own forces and that of the followers of Sebastian Thor, a charismatic Imperial preacher whose own orthodox sect of the Imperial Cult, the Confederation of Light, sought to reinstate the orthodox rites and rituals of the Adeptus Ministorum that Vandire had banned in an attempt to reshape the Ecclesiarchy to serve his own power. The Reign of Blood that lasted for seven decades and was intended to make Vandire the sole de facto ruler of the Imperium was only brought to an end when Vandire was slain by his own all-female bodyguards, the Brides of the Emperor. The Brides were reshaped after the Reign of Blood to become the Adepta Sororitas, the Sisters of Battle, the military arm of the Adeptus Ministorum. The Imperial Inquisition also added a third arm to its organisation, the Ordo Hereticus, which was intended to root out the internal enemies of the Imperium and prevent the emergence of another Goge Vandire who sought to serve his own selfish ends rather than the will of the Emperor.

The Age of Redemption (c. M37)

The Age of Redemption marked the era when the Imperium recovered from the sins of apostasy in a rain of blood and tears. The Imperial Cult grew in zeal as never before. Heretic pyres burned night and day on a thousand Imperial worlds as the people of the Imperium sought to mortify their sins against the God-Emperor through the scourging of the flesh of others. Crusade after crusade was launched by the Space Marines and other Imperial military forces to recapture the lost wealth of the Imperium and push back the hordes of Chaos, Orks and other alien threats to humanity. This religious fervour eventually peaked in an orgy of fanatical devotion to crusading in the Emperor's name and thousands of worlds were left with inadequate defenses as sector fleets of the Imperial Navy, Space Marine Chapters and Imperial Guard Regiments are drawn into longer and more terrible Redemption Crusades spurred on by this religious fanaticism.
Among the most devastating of these conflicts were the Abyssal Crusade and the Occlusiad. The Abyssal Crusade of 321.M37 began when Saint Basilius found thirty Space Marine Chapters wanting in their devotion to the Emperor. The guilty embarked upon a crusade into the Eye of Terror to earn their salvation and purge those human-settled worlds stolen from Mankind by the birth of the Dark Prince of Pleasure, Slaanesh. The Occlusiad of 555.M37 started when the northwestern fringe of the galaxy was ravaged by the heretics known as the Apostles of the Blind King, rogueTech-priests who viewed humanity as an utter affront to the Machine God. The Apostles had uncovered wondrous artefacts from the Dark Age of Technology that made possible the transformation of ordinary stars into supernovae. The constellations of the galaxy were changed forever when the Apostles purged the outer Segmentum Obscurus of human life using these weapons. War raged for a decade until the Navigator Joyre Macran discovered the palace-warship of the Blind King hidden in a fold of the Warp. Escaping with this crucial intelligence, Macran guided the Imperial Navy's Emperor-class battleship Dominus Astra to the palace's location. The Blind King was killed and the genocide ended when the Dominus Astra's lance batteries pierced the palace-warship's hull and without his leadership the Apostles were swiftly overcome and their weapons hidden away in the vaults of Mars.

The Waning (c. M38 - c. 750.M41)

With the Imperium's military forces in every branch utterly exhausted by the Redemption Crusades, star system after star system fell to Ork invasion, Chaos insurgence or sheer rebellion. Anarchy throughout many sectors of the Imperium was rife during a dark period in Imperial history that is now called the Waning. Ever more star systems are turned over by the Administratum to direct rule by Space Marine Chapters to preserve stability as only the Astartes possess the inviolable military strength required to restore Imperial control in the more lawless regions of the galaxy.
This period sees the Macharian Conquests (also called the Macharian Crusade) of 392-399.M41 during which Lord Commander Solar Macharius, master of the Segmentum Solar, mustered the greatest human army the galaxy had seen since the Great Crusade. In only five standard years, Macharius reconquered a thousand worlds on the western reaches of the Imperium and his glory carried him into the darkest sectors, places where the Emperor's light had never been known. Upon his death, the whole Imperium wept for the lost commander, but Macharius' conquered territories soon collapse into rivalry and civil war. The Macharian Heresy, as this time is now known, lasts for seventy years and is only ended through the combined efforts of one hundred Space Marine Chapters.

The 12th Black Crusade, or Gothic War, was a vast campaign launched by the Chaos Space Marine Warmaster Abaddon of the Black Legion which engulfed the Gothic Sector of the Segmentum Obscurus. It consisted of hundreds of planetary invasions and naval battles spanning the time period 139.M41 - 160.M41 and only ended when Abaddon and his Chaos Space Marines were forced to retreat into the Immaterium with the arrival of Imperial reinforcements. It saw the destruction of several planets and four of the six irreplaceable ancient alien artefacts known as the Blackstone Fortresses as well as the deaths of millions, if not billions, of Imperial citizens.

The Time of Ending (c. 750.M41 - Present)

As the threats to the Imperium grow, Mankind stands on the precipice of utter extinction. The Time of Ending is the era of humanity's judgment, where faith shall be tested by fire and all men's courage will be pushed to its limits--and well beyond. Secession, rebellion, Chaos corruption and heresy are now rife within every corner of the Imperium. Sensing weakness, alien empires ancient and new to humanity's experience--Orks, Eldar, Tau, Necrons and perhaps worst of all, the Tyranids--close in from every side. The Space Marines and Imperial Guard are at war as never before, even during the Horus Heresy, defending humanity from threats within, without and beyond the boundaries of reality. This is surely humanity's darkest hour.
The Time of Ending is so named in 744.M41 when Taggarath, the Seer of Corrinto, proclaims the approach of the End Times. He prophesies a time of unprecedented upheaval, in which even the light of the Emepror is swallowed in darkness. Taggarath is swiftly executed by the Inquisition for heresy--and to keep his prophecies unknown by the wider Imperial public.

In 745.M41 the Tyranids first enter the galaxy and the Tyrannic Wars begin. Hive Fleet Behemoth destroys the Imperial star systems of Tyran (for which the Tyranids are named) and Thandros. Later that same year, Hive Fleet Behemoth descends upon the Realm of Ultramar, the fief of the Ultramarines, laying waste to several worlds and badly damaging the Space Marines' greatest Chapter. The threat of Hive Fleet Behemoth is ended under the guns of two entire Imperial Navy battlefleets. Imperial Commanders across the Ultima Segmentum look to their borders with growing unease.

757.M41 sees the first recorded incidence of the dread Zombie Plague on the world of Hydra Minoris. A quarantine is imposed by the Imperial Navy, trapping 23 billion uninfected people alongside a rising tide of the hungry and mindless undead of Nurgle.

In 963.M41 the Imperium made first contact with the Tau Empire when the Ultramarines clashed with a Tau expeditionary fleet for control of the cursed planet of Malbede. When the conflict awakened the Necrons whose tombs were hidden on Malbede, the Ultramarines joined the Tau in a temporary alliance to defeat the emerging Necrons. In the wake of the battle, Exterminatus is proclaimed on Malbede by the Ultramarine Chapter Master Marbeus Calgar, but he generously allows the Tau to evacuate before the surface of the planet is destroyed. Unfortunately, the Imperium of Man now finds itself facing two more alien enemies--the humanoid Tau who seek to expand their growing interstellar empire to "serve the Greater Good" and the unholy Necrons who seek to wipe the galaxy clean of all sentient life once more as sacrifices to their vile Star Gods, the C'tan.

In 993.M41 the Ultramarines crush a rebeliion on the industrial world of Ichar IV, only to find themselves in the forefront of a desperate defence against the arrival of the Tyranids' Hive Fleet Kraken. Elsewhere, the Eldar Craftworld Iyanden is ravaged by other tendrils of the Kraken. Two Space Marine Chapters--the Scythes of the Emperor and the Lamenters--are all but wiped out by the Hive Fleet and hundreds of Imperial worlds are lost to the ravenous Tyranids before the incursion is finally halted.

In 997.M41 humanity peers into the abyss when the twin tendrils of Hive Fleet Leviathan emerge from intergalactic space and strike at the underbelly of the Imperium from below the galactic plane, cutting a swathe of truly horrific destruction through Segmentum Tempestus, Ultima and Solar. It becomes clear that the two previous Tyranid incursions into the galaxy were only reconaissance expeditions for the main Hive Fleet.

In 999.M41 Abaddon the Despoiler launches the 13th Black Crusade out of the Eye of Terror with the intent to seize the world of Cadia and the Cadian Gate it defends and so allow the Forces of Chaos to assault the heart of the Imperium for the first time since the Horus Heresy. The Imperium is forced to mobilise the largest military force in its history since the Heresy to meet the massive Chaos assault. The valour of the Imperial defenders is ultimately rewarded. Though the Forces of Chaos manage to secure a foothold on the surface of Cadia, the Imperial Navy defeats the Chaos warfleets in orbit of the fortress world and traps the Chaos armies on the world below. As long as the Imperium can maintain its orbital superiority, a stalemate will be maintained. However, defending that stalemate grows more difficult with every passing month as the Tyranids of Hive Fleet Leviathan march ever closer to Terra, drawn by the light and power of the Astronomicon in the Warp inevitably towards the heart of the Imperium. The heroism of the Space Marines and the Inquisition manages to slow down the progression of the massive Hive Fleet, but its ultimate objective is never in doubt.

Finally, even as multiple calamities loom over the Imperium, the Adeptus Mechanicus has learned a terrifying secret: the mechanisms of the Golden Throne have begun to fail and they no longer possess the knowledge required to repair that ancient piece of technology. Unless something can be done, the God-Emperor will die and then humanity will face the drawing darkness alone...

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