Age of the Imperium

The Age of the Imperium is the name given by Imperial lexographers and historians to the period of human history that represents the present time in the Warhammer 40,000 universe. The Age of the Imperium began in the 30th millennium when the Emperor of Mankind emerged from long centuries of obscurity to unify Terra beneath his rule and end the terrible suffering and civil conflicts of the Age of Strife. The Emperor forged a political and military alliance with the Mechanicus Cult that had reunified the Forge World of Mars beneath its rule and together the two most populous worlds of humanity forged the Imperium of Man. Using the advanced technology of the Mechanicus, the Emperor created the twenty Space Marine Legions of the First Founding to launch the Great Crusade, an attempt to reunify all the human-settled colony worlds across the galaxy under a single government once more.

The Rise of the Emperor (c. M31)
During the Age of Strife the great Warp storms that heralded the birth of the Chaos God Slaanesh from the Fall of the Eldar had separated Terra from its interstellar colonies and plunged all the human civilizations across the Milky Way Galaxy into disarray and chaos. When the storms abated with the emergence of Slaanesh in the Warp, a new leader for humanity known only as the Emperor emerged on Terra, the ancient homeworld of mankind. He conquered the raging warlords of late Age of Strife Terra and entered a military and political alliance with the Cult Mechanicum on Mars. With his twenty Legions of genetically engineered Space Marines created from the the genetic material of the Primarchs, the Emperor planned to reunite all of mankind beneath his benevolent rule, banishing the violence, superstition and injustice that had ruled humanity during the Age of Strife.

The Great Crusade (c. M31)
The Great Crusade lasted for 200 standard years and brought many long lost star systems into the fold of the newborn Imperium of Man. Under the War Council of the Emperor and his rediscovered Primarchs, vast Expedition Fleets comprised of the Imperial Army and the twenty Space Marine Legions fought back aliens, feral humans tribes, petty human dictators and the Warp-tainted forces that had gained control of large portions of human-settled space during the Age of Strife. Once a human-settled world had been pacified, it was brought into "Imperial Compliance" by a new Imperial Planetary Governor chosen by the Emperor and it was often occupied by a unit of the Imperial Army that was left behind to complete the integration of the planet into the Imperium while the Expedition Fleet moved on to its next target.

The Horus Heresy (c. M31)
The Great Crusade ended with the nightmarish Imperial civil war known as the Horus Heresy. The Warmaster Horus, the greatest among the Primarchs, leader of the Luna Wolves Space Marine Legion and the most favoured son of the Emperor, fell under the influence of the Ruinous Powers of Chaos. In an attempt to usurp his creator and take his place as the ruler of mankind, Horus took control of a third of the entire Imperium's armed forces (including a full half of the Space Marine Legions and much of the Imperial Army and the Adeptus Mechanicus) and marched towards Terra where his forces laid siege to the Imperial Palace. He was ultimately slain aboard his own flagship during a daring assault by Loyalist forces, but the Emperor was mortally wounded in the final battle and was forced into a state of semi-consciousness on the cybernetic life support system known as the Golden Throne. The Imperium was left rudderless and at the very brink of collapse following the Heresy.

The Age of Rebirth (c. M31 - c. M32)
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 Marines from human space. Eventually the Chaos Marines and the Ruinous Powers' other followers found refuge in the massive Warp incursion 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 back 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 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 command structure and bureaucracy. The remaining Loyalist Space Marine Legions adopted the Codex Astartes written by the Ultramarines' Primarch Roboute Guilliman and were split into many smaller Space Marine Chapters that were comprised of only 1,000 men each along with their own supporting spacecraft and planetary fiefs.

The byzantine politics of the Imperium took a calamitous turn in 546.M32 when the High Lords of Terra are 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 Sabe Swords Chapters tracks the Grand Master to an Assassinourm temple. The commander of the strike force is assassinated as soon as he makes planetfall, but the Brother Marines carry out the attack without him. Inside the temple they were attacked by 100 Eversor Assassins. Only a single Space Marine survided 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 historians of the Adeptus Mechanicus 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 interstellar economy due to the rediscovery of a valuable 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 is 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 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 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 years. 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 against 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.

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 Administratum. Vandire plunged the Imperium into a civil war 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 Adeptus Sororitas, the Sisters of Battle, the military arm of the Adeptus Ministorum. The Imperial Inquisition also added a third arm, 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 seek to mortify their sins against the God-Emperor through the scourging of the flesh of others. Crusade after crusade is launched by the Space Marines and other Imperial military forces to recapture the squandered wealth of the Imperium and push back the hordes of Chaos, Orks and other alien threats to humanity. This religious fervour eventually peaks and thousands of worlds are 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 are 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 borth of the Dark Prince of Pleasure, Slaanesh. The Occlusiad of 555.M37 began when the northwestern fringe of the galaxy was ravaged by the heretics known as the Apostles of The Blind King, rogue tech-priests who viewed humanity as an utter affront to the Machine God. The Apostles uncovered wondrous artifacts 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 Obscuris 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 falls to Ork invasion, Chaos insurgence or sheer rebellion. Anarchy throughout many sectors of the Imperium is 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 of 995.M40 when Lord Commander Solar Macharius, master of Segmentum Solar, mustered the greatest human army the galaxy had ever seen. In only five years Macharius reconquers a thousand worlds on the western reaches of the Imperium and his glory carries him into the darkest sectors, places where the Emperor's light had never been known. Ipon his death, the whole Imperium weeped 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 Marine Primarch Abaddon of the Black Legion which engulfed the Gothic Sector of the Segmentum Obscuris. 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 Marines were forced to retreat to the Immaterium with the arrival of Imperial reinforcements. It saw the destruction of several planets and four of the six irreplaceable 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. Now is the time of 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--Orks, Eldar, Tau, Necrons and 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.

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. Lather that 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.

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 temproary 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 rebeliion on the industrial world of Ichar IV, only to find themselves in the forefront of a desperate defense 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 Lamentors--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 stopped.

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 Segmentums Tempestus, Ultima and Solar. It becomes clear that the two previous Tyranid incursions were only reconaissance expeditions for the main Hive Fleet.