The History of the Imperium

Early History

Rise of the Emperor

During the Age of Strife Warp storms had separated Terra from its colonies and plunged disparate human civilisations across the galaxy into disarray and chaos. When the storms abated, a new powerful leader called the Emperor emerged. He conquered Terra and entered an alliance with the Mechanicum on Mars. With his Legions of genetically engineered Space Marines, he planned to reunite mankind.

The Great Crusade (c.M31)

The Great Crusade lasted 200 years and brought many long lost systems into the fold of the Imperium. Under the War Council of the Emperor and his Primarchs, vast Expedition Fleets of the Imperial Army and Space Marine Legions fought back aliens and warp tainted forces that had gained a foothold in the domain of man during the Age of Strife.

Horus Heresy (c.M31)

The Great Crusade ended with the Horus Heresy. Horus, greatest among the Primarchs and the favoured son of the Emperor fell under the influence of the Gods of Chaos. In an attempt to usurp his creator and take the place as Emperor of mankind, he took control of a full third of the whole Imperium's armed forces (which included half of the Space Marine Legions) and marched towards Terra. He was ultimately slain, but the Emperor was mortally wounded and the Imperium left at the brink of collapse.

Ages of the Imperium

The Age of Rebirth (c.M31 - c.M32)
During the Age of Rebirth the Imperium slowly recovered from the Horus Heresy.

The wars of the Great Scouring were fought in the decades after the Horus' demise. In a lengthy campaign the Imperium hunted and banished the remaining traitors from their realm. Eventually the followers of Chaos found refuge in the Eye of Terror.4 At the same time many alien races that had been fought back during the Great Crusade reappeared and plagued the vulnerable worlds of man.2b
In order to prevent a single person from controlling as much military power as Horus did and thus eliminating the risk of another large scale military rebellion, numerous reforms were drawn up. The Imperial Army became the Imperial Guard, and their link to the Imperial Fleet was severed. The remaining loyal Space Marine Legions adopted the Codex Astartes written by Primarch Roboute Guilliman and were split into several smaller Chapters.

The Forging
The Forging is also known as the Golden Age of the Imperium.

During this period the Adeptus Terra brought the most important systems under its control and expanded the borders of the Imperium. Internal stability was gained with the establishment of Astropath Choirs on countless worlds and the discovery of valuable STCs from the Dark Age of Technology. Once more the Imperium expunged the forces of Chaos and Xenos alike in the galaxy and reclaimed lost regions.

The Nova Terra Interregnum
The Nova Terra Interregnum is also known as the time of twin Empires and lasted for 9 centuries.

The Ur-Council of Nova Terra dismissed the authority of the High Lords of Terra and claimed rule of the Segmentum Pacificus.
During the Cataclysm of Souls in 975.M35 the Ecclesiarchy tried to unite the Imperium as a religious state. Their efforts ended in massive religious wars against the Ur-Council.

The Age of Apostasy (M36)

The Age of Apostasy is renowned for the Reign of Blood, the time of Goge Vandire's rule as Ecclesiarch and Master of the Administratum. Vandire plunged the Imperium into a civil war that lasted for seven decades.

The Age of Redemption

Beginning with the Great Cull by the High Lords of Terra, thousands of worlds glow with the pyres of heretics burning. The Imperial Cult grows in power as never before, as those who defy the Ecclesiarchy are purged in blood and tears.1 A multitude of crusades are launched to recapture the squandered wealth of the Imperium. Saint Basillius judges that thirty Space Marine Chapters are found wanting and they embark on a crusade into the Eye of Terror, intent on purging those worlds stolen by the birth of Slaanesh.1
At the height of this fervour thousands of worlds are left inadequately defended as sector fleets, Imperial Guard regiments & chapters of Space Marines are sent on increasingly longer and more terrible crusades.

The Waning

With the Imperium's military resources exhausted due to the religious crusades during the Age of Redemption, Ork and Chaos forces are able to overwhelm many planets and systems. More and more Space Marine Chapters are granted control over systems in order to retain stability.

The Time of Ending (c750.M41 - onwards)
These are the closing years of the 41st millennium.

The galaxy has become an increasingly hostile place and the realm of the Imperium has begun to crumble. The light of the Astronomican is fading and the Golden Throne upon which the Emperor has rested for ten millennia is discovered to have irreparable failures.


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