The Chaos Gods fed Horus' innate ambition and sense of betrayal by the Emperor until he turned upon his father and sought to claim the Imperium of Man for his own. The civil war began following the corruption by the Ruinous Powers of Chaos of the Imperial Warmaster Horus Lupercal, the primarch of the Sons of Horus Legion and the most beloved genetic son of the Emperor. The Horus Heresy is in many ways the founding event of the Imperium of Man as it now exists. Its outbreak marked the end of the Emperor of Mankind's Great Crusade to reunite the scattered colony worlds of Humanity in the Milky Way Galaxy under a single government and the beginning of the current Age of the Imperium. The Horus Heresy, sometimes referred to poetically as the ' Age of Darkness,' was a galaxy-spanning civil war that consumed the worlds of Mankind for 9 Terran years. From the final testament of Sulem Rei, historiarch of the Imperial Court, presented to the High Lords of Terra circa 098.M32Įmperor of Mankind mortally wounded and placed within the Golden Throne Horus slain by the Emperor Traitor Legions broken and flee towards the Eye of Terror true beginning of the Age of the Imperium It is the curse of history that few care to remember other than those fragments that exalt them, to relive those glory days endlessly while the present crumbles about them.' For those were the last days of legend, when the Emperor and His sons, the mighty Primarchs, strode forth to war, when the dominion of Mankind spread across the galaxy and none could challenge our might, the last days of a golden age long since consigned to dust by the actions of one man. Even now, centuries after its end, when few save ancient and shrivelled creatures such as myself remember the horror of those dark years, men speak of it with awe. ' Of all the conflicts that have beset this Imperium of Mankind, it is the rebellion of the Warmaster Horus, the Horus Heresy, which has left the greatest scars upon its fabric. Attributed to Roboute Guilliman, Lord of Ultramar and Primarch of the Ultramarines Legion Their very belief systems have been warped. But we have seen them, how their minds and bodies have been corrupted.

To turn against brothers, to kill for personal advancement and power. For a complete chronology of the events of the Horus Heresy please see Horus Heresy Chronology

Horus heresy chronological order