Great Crusade

### Strength (Attackers)

Legiones Astartes, Imperialis Armada, Imperial Army, Legio Custodes, Departmento Investigates, Legio Titanica, Mechanicum military forces

### Casualties (Defenders)

High, many xenos species were driven to exctinction while human worlds that refused to accept Imperial Compliance suffered often bloody assaults with high casualties

### Status

Incomplete Imperial victory; Great Crusade interrupted by the outbreak of the Great Secession

### Outcome

Large swathes of the galaxy were unified under the rule of the Imperium of Man

The **Great Crusade** was the period in the early history of the Imperium of Man, lasting from approximately 798.M30 into the first decades of the 31st Millennium (approximately a little over two standard centuries), when the Imperium was expanding as it sought to bring all of human-settled space back under the control of a single ruler, the Emperor of Mankind.

The Great Crusade marked an era in human history of rebuilding, reunification and rapid technological advancement following the complete regression of Mankind into techno-barbarism during the 5,000 Terran years of the Age of Strife. The Great Crusade era was considered the Golden Age of the Imperium before true enlightenment, peace and prosperity were achieved in the wake of the Great Secession.

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 Milky Way Galaxy, which He judged to be necessary if humanity was to survive the never-ceasing threats to its existence embodied by Chaos, myriad xenos races and its own fragile human nature.

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 that would form the core of the later Adeptus Astartes and the Imperial Army to serve as a support and garrison force for the Astartes. The use of accelerated gene-culturing of gene-seed organs to fill the need for vast numbers of Space Marines later led to the development of genetic flaws in many of the Legions.

These forces, with the technological and military aid of the Mechanicum as required by the Treaty of Mars, would bring the light of the Imperial Truth and enforce Imperial Compliance with the new regime on every human world encountered. At its peak in the early 31st Millennium,over two centuries after its inception, 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 artists and journalists, were sent out with these fleets in the final days of the Great Crusade to record for posterity in pictures, words and music all that the Imperial warriors of the Crusade were accomplishing in the name of Mankind.

Finally, 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 and convince their populations of the benefits to be had from Imperial rule.

The Great Crusade was under the direct command of the Emperor of Mankind for the duration of the Great Crusade, but in truth, he had left much of the runnings of the undertaking to his Primarch's, instead occupying his time with a secret project deep within the Imperial Palace to open the labyrinthine interdimensional Aeldari Webway to humanity's use so that the Imperium could be tied together as never before and forever shielded from the depredations of the Warp. It was this project however that would be discovered by the Umbral blades at the end of the Great Crusade, the Emperor's desire for total secrecy causing the Imperium itself to fracture under its weight.

## History

### The End of the Age of Strife

   During the Age of Strife the Emperor, who had spent all the years of His immortal life since His birth in the 8th Millennium B.C. seeking to guide Mankind to a better destiny, was trapped on the techno-barbarian-ravaged Earth. This was due to the massive Warp Storms prevalent throughout the galaxy in the 5,000 standard years before the birth of the Chaos God Slaanesh once more made travel and astropathic communication through the Warp possible.

Not content to simply sit back while humanity suffered through the long years of Old Night, the Emperor of Mankind spent this time performing intensive biological research on the human genome in gene-laboratories hidden deep below the Himalazian (Himalayan) Mountains, seeking a way that he could ultimately reunite all of humanity so that it could once more pursue its destiny of taking control over the Milky Way Galaxy as other intelligent species like the Eldar had already done.

The Emperor, who did not bear that title at this early date, had always worked to advance His agenda from behind the scenes and a long list of different identities over the millennia, some of them very well-known. But to save Mankind from the disaster of the Age of Strife, it had become apparent that He would have to take a far more open political role than He had previously preferred if the human race was to be saved from ultimate extinction.

The result of His scientific work was the creation of the first prototype supersoldiers who would serve as a template for the later development of the Space Marines. Using these first genetically-engineered supersoldiers called the Thunder Warriors, the Emperor unleashed the Unification Wars upon the techno-barbarian tribes and nation-states of Terra, forcing them to unite under a single government represented by a banner called the Raptor Imperialis with Himself taking the title of the "Emperor of Mankind" after years of savage warfare. This event was later known in Imperial records as the Unification.

After this, the Emperor realised that to reunite all of humanity, He would need generals and proconsuls in addition to Himself whom He could trust absolutely and who possessed capabilities similar to His own. So he ordered the creation of 21 highly advanced, genetically-engineered transhumans known as the Primarchs. These men, created using the Emperor's own genome as the foundations of their genetic code, were intended to lead the reunification of Mankind.

The Ruinous Powers of Chaos, however, fearful of the affect the Emperor's plans would have upon their own power within the Immaterium since they were dependent upon mortals for their very existence, managed to bypass the arcane wards protecting the Emperor's secret gene-laboratory under the Himalazian mountains, and teleport the unborn Primarchs, still in their gestation capsules, away from Terra. They were scattered across the galaxy to different human-settled worlds and several were tainted with the touch of Chaos that would bloom in time.

Facing this setback, the Emperor decided to change His tactics if not His ultimate goal of reunification. He gathered the remaining genetic material that had been used to create the Primarchs and from it cultured thousands of sets of gene-seed. These could be gestated into individual sets of 19 separate organs that when implanted within the body of an adolescent human male would transform him into one of the transhuman warriors known as the Astartes in High Gothic, the first true Space Marines.

The Emperor raised 20 Legions of Astartes, each making use of gene-seed organs cultured from the DNA of one of the Primarchs, or the twinned Primarch's in case of the IIIrd, from among the population of a newly unified Terra. After five millennia and the birth of Slaanesh following the events that led to the Fall of the Eldar, the massive Warp Storms finally dissipated across the galaxy. With their absence allowing interstellar travel once again, the Emperor quickly moved forward with his plans to begin the conquest of the galaxy.

### Mars and the Adeptus Mechanicus

The Emperor's first obstacle to the reunification of Mankind was the existence of the Mechanicum empire of the Tech-priests of the Cult Mechanicus on Mars, who had historically been fiercely independent of Earth. Instead of an outright war, the Emperor used the threat of an assault by his Space Marines on Mars and the offer of new technologies to form an alliance in the 30th Millennium with the Tech-priests of what would later be called the Adeptus Mechanicus. This alliance formed the heart of the newborn Imperium of Man and was symbolised by the adoption of the two headed-eagle or Aquila that is still the primary icon of the Imperium.

Despite his disdain for their reliance on religion and cybernetic augmentation of their bodies, the Emperor knew that He would need Mars' great manufactoria (factories), mechanical output and ancient technological knowledge to build the military force required to reunify humanity across the galaxy, and He incorporated them into the Imperium.

The Tech-priests of Mars, likewise, saw the Emperor's extraordinary scientific knowledge and technological skill as proof that He was the Omnissiah, the living avatar of their Machine God in the material realm, who the creed of the Cult Mechanicus had promised would return one day to the Red Planet and offer the true way forward for humanity.

### The Conquest of the Void

The Great Crusade was the largest and most ambitious military endeavour ever undertaken by Mankind. As mighty and valiant as the hosts of the Emperor were, this epic undertaking would have been entirely impossible without the countless thousands of Warp-capable vessels that transported hundreds of thousands of the superhuman warriors of the Space Marine Legions and many millions of Imperial Army soldiers from one star's light to the next.

The Great Crusade saw a staggering array of vessels constructed, reclaimed or pressed into service. Some were used for a matter of solar months before being declared obsolete or wearing out and degrading to destruction, quite apart from losses incurred in battle, while others gained a permanent place in the canon of war, with successful designs endlessly copied and modified as the decades progressed.

The first vessels to enter the service of the Imperium were constructed in the orbital foundries of Terra, and later Mars' Ring of Iron and the orbital shipyards of Saturn, under the scrutiny of the Emperor and the Forge-wrights of the Mechanicum, and indeed it was only that in alliance with Mars that the trans-solar expansion was possible in any meaningful way. This was further aided when at last the Saturnyne Dominion, with its accomplished ship-masters, joined the Imperium after their alien overlords were overthrown, and as the Imperium expanded, many more great orbital shipyards were added at Voss, Grulgarod, Lorin and Cypra Mundi. All these grew to near rival Mars itself in voidship production.

Driven by the will of the Emperor, the first Expeditionary Fleets pushed outwards into the galaxy. Preceding each great Expeditionary Fleet of hundreds, sometimes thousands, of vessels often ranged smaller contingents of independent flotillas led by a class of martial leader that would become known as the Rogue Traders Militant. Many of these individuals were former rulers of the numerous realms the Emperor had cast down first during the Unification Wars and later as the Great Crusade spread, formerly independent human worlds.

They were offered a stark choice--bend the knee before the Emperor and swear service to the Great Crusade, or die by His hand. Though many set pride before what they regarded as slavery, others chose service and took up the Emperor's Warrant of Trade. There was a price, however. The Rogue Traders Militant were expected to scout ahead of the leading edge of the Great Crusade, accompanied by their own armies as well as whatever assets had been ceded them by the Emperor.

Operating so far ahead of the Emperor's crusading armies, the Rogue Traders Militant could expect little or no aid should they encounter foes too powerful for them to overcome. After several solar decades penetrating the inky black of the void, Rogue Trader Militant fleets often appeared as ramshackle vagabonds, many of their starships taken from defeated enemies, sometimes including xenos vessels of entirely novel or esoteric form.

They were forbidden to return to Terra, for in His wisdom the Emperor sought not to just rid Himself of powerful rivals, but to ensure that even in their deaths they might serve Mankind. Many vanished alone and unheralded; slain, consumed or enslaved by nameless xenos abominations far from the light of Terra.

As the Imperium expanded, so too did its fleets. Countless long-lost wonders of technology were recovered, some wrested from the dead hands of unwilling custodians, and others surrendered willingly as fitting tribute to the Master of Mankind. Some of these patterns and classes proved possible to reproduce and replicate, and before long the various arms of the Imperium's military acquired their own distinctive panoply of warships.

Those of the *Legiones Astartes* were often blunt of prow and slab-armoured, built to endure the withering storm of fire that accompanies a planetary invasion, their plasma furnace-hearts powering some of the most destructive weapons known to Mankind.

The ships of the Emperor's wider naval armadas, the *Armada Imperialis*, were more diverse affairs, built for void supremacy. They ranged from stately Battleships, multi-kilometre long engines of doom, their armour concentrated to the fore and their flanks repleted with rank upon rank of broadside batteries, to lithe and deadly Destroyers and stripped-bare Warp Runners, to watchful piquet Frigates and lumbering star fortresses. Beyond these were innumerable classes of transports, arks, conveyers and supply ships, the forge vessels of the Mechanicum and their own strange space-going engines of war.

### Rediscovery of the Primarchs

Even with access to the vast fleets of starships and military materiel that the forges of Mars could churn out, the expansion outwards into the galaxy from Terra was slow, primarily due to a lack of the necessary manpower and skilled leadership. Without access to the Primarchs' unique genomes, the time required to create a Space Marine was far longer than ideal. The Emperor was also adamant that all the genetic material for new Astartes gene-seed must come directly from Him, to keep the gene-seed organs pure and 100% effective, as mutation had a habit of setting in even at this early date in the Astartes' existence.

Only a short time after he had launched the great expedition to reunite Mankind that he called the "Great Crusade," the Emperor was reunited with one of His Primarchs after His Great Crusade Expeditionary Fleet, the *Pricipia Imperialis*, completed one of its first journeys through the Warp; this was Alexios Justarion, the genesire of the Xth Legion. Being the first Primarch rediscovered by the Emperor, the first of His beloved sons who had returned to Him, Antarus and the Emperor soon formed a truly unique bond of friendship and paternal love, saving one anothers' lives on many occasions.

Antarus was given command of the Xth Legion of Space Marines, the Paragon Order, and he soon set the precedent for raising all future Astartes for his Legion from among the men of his former homeworld. With the increased Space Marine production made possible by direct access to a Primarch's genome, the Great Crusade began picking up steam, with the Emperor's "Imperium of Man" bringing many new worlds into "Imperial Compliance" either through negotiation and diplomacy or outright conquest when all other methods failed.

Each world was also introduced to the Imperial Truth, the Emperor's chosen philosophy and the foundation for Imperial culture, which was stridently atheistic and rejected all forms of human religion or spirituality as mere superstition to be replaced by the cold rationalism of scientific progress. Though the Emperor loathed war, He understood that if Mankind was to survive the rigours of a hostile universe it must stand united, and that unity must be brought quickly, even if it had to be forced in certain instances.

After 10 Terran years of successful crusading, the Emperor discovered another of the Primarchs, the Psychic Lord, Camelous on the great Agri-world of Pax. Although Antarus was pleased at the discovery of one of his brothers, he secretly hoped to always remain the Emperor's favourite son, no matter how many of his brothers were rediscovered.

Over time, all of the Primarchs were rediscovered by the various Expeditionary Fleets of the Great Crusade and given command of the Space Marine Legion for which their genetic code had been used as the foundation of that Legion's gene-seed.

The Order of the Primarch's discovery is as follows:

The Crusade also grew larger as the solar decades of conquest passed. With each new world brought into Imperial Compliance and made accepting of the Imperial Truth, its resources could be harnessed for the construction of ever more starships and the massive amounts of materiel needed to keep the entire enterprise moving forward. With the rediscovery of all of the Primarchs, the time required for Space Marine production was dramatically decreased; a new Astartes ready for combat could be created in as little as a standard year at the height of the Great Crusade.

This rapid creation process, however, would prove disastrous: mental defects and unique eccentricities began to creep into the ranks of the Astartes as the manpower needs of the Great Crusade called for larger and larger armies. Yet, by the early 31st Millennium, 202 standard years after it had begun, the Great Crusade had reunited vast swathes of the galaxy under the leadership of the Emperor of Mankind, seemingly initiating a new Golden Age of progress and reason for the human race.

### Blood and Illumination: The Pax Imperialis

> There is no salvation from the darkness in men's hearts.
>
> Ancient Terran Proverb

The Great Crusade brought peace to Mankind, ending wars between peoples and nations, binding all together in unity. It broke the chains of superstition and freed billions from the whims of tyrants and murderous xenos. Where before there had been strife and the cloud of ignorance, now there would be peace and truth. These were high ideals indeed, but ideals that came at a price. Mankind had to be dragged to illumination, and many tried to pull it back into the shadows, into the old ways of ignorance and discord.

The Emperor had unified Terra not only through words and alliances, but also through force of arms. Illumination and peace had to be won by blood. This was the basic truth of the *Pax Imperialis*, and when the Great Crusade took to the stars, this truth went with it. But it was not only in open war that the blood price for universal peace had to be paid. The enemies of the Imperium were manifold, and even before the Great Secession, there were those who nurtured treachery in their hearts, who mouthed words of loyalty whilst seeding discord. While the ideals of the Great Crusade saw warriors marching in open war, the truth was that there were other methods and other less noble battles fought to keep the peace.

The Assassin Temples, the networks of informers and the Silent Agents of Malcador the Sigilite, the Annihilation Protocols, and the ancient and all but forbidden weapons wielded by a chosen few in the Legions or en-masse in the XXth, all these were the tools and warriors by which the Imperium enforced its ideals and, for a time, brought peace to the galaxy. For the Emperor, the end justified the means in the pursuit of His great dream, for He knew better than most, that His time was limited. Mankind must be united and ready to face the future before the Chaos Gods could unite to stop Him.

### Fractures in Loyalty

As the Imperium grew and the Great Crusade fractured into hundreds of different Expeditionary Fleets that could be separate from one another for solar decades of relative time, the Primarchs and their Emperor began to grow distant from each other. The Iron Lords Legions grew infamous for their utterly detatched and seemingly callous murder or entire worlds simply to make examples for the conquest of further new worlds, the Supernal Seraphs pursuit of knowledge saw the legion fall to the darker things that lurked within the warp, put down by the Angelis Noctem.

The Imperial Army, composed almost entirely of normal human soldiers (some regiments such as the Geno Two-Five Chilliad were the products of selective breeding and genetic-engineering dating back to the Unification Wars to produce more capable soldiers or officers), provided much-needed manpower for garrison and support duties for the planets brought into Imperial Compliance by the Crusade.

Freed from garrison duties, the Space Marines who comprised the core of each Expeditionary Fleet could conquer yet more worlds in a shorter space of time. Many Astartes and Imperial Army soldiers began speaking only of their loyalty to the Primarch that they served, and not to their Emperor, something that would eventually aid the Secessionist cause during the Great Secession.

## Expeditionary Fleets

During the Great Crusade, the vast forces of the Emperor were organised into a number of different formations which became known as the Expeditionary Fleets. At first there were but twenty one fleets, the 2nd through to the 21st commanded by the legions, while the first and mightiest of these was commanded by the Emperor himself, known as the *Principia Imperialis,* but as the Crusade spread across the galaxy more and more were launched. Some were still commanded by legions, especially as their numbers began to swell as the crusade wore on, but others were entrusted to mortal warriors, generals whose skill or heritage made them the masters of the greatest military undertaking known to mankind.

In order that they could be effectively supported and their movements across the galaxy tracked with some degree of accuracy, each of the Expeditionary Fleets was designated a number by the War Council. As the Great Crusade drew to a close in the early 31st Millennium, some 257 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 over 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.

The composition of each of the fleets was not fixed. The various fleet groups, Imperial Army regiments, auxiliary troop formations and even Space Marine Legions that made up a fleet could come and go over time, as prevailing strategy dictated. But the designation numbers remained and, while most never held any particular significance, some became famously associated with specific Primarchs or other prestigious leaders of the Imperium.

The numerical designation of an Expeditionary Fleet was also applied to worlds conquered by its forces -- for example the Imperial world initially known as 30-206 was the two hundred and sixth world discovered by Shaaa Hydrade's 30th Expedition. It was therefore possible for the Imperium's administrators to plot the movements of a specific fleet by the worlds it encountered, in chronological order.

While all of the original Expeditionary Fleets had been assembled in Terran space by the Mechanicum, by the height of the Great Crusade they had been dispersed throughout the Milky Way Galaxy to reunite all the human-settled colony worlds under the Emperor's rule to bring to fruition His dream of a united human race dominating the stars. The Expeditionary Fleets were given a broad remit to bring human-settled worlds into the Imperium by diplomacy if possible but by force if necessary, and to cleanse any xenos species from the galaxy who represented a threat to humanity.

As almost all intelligent alien species encountered by Mankind had proved hostile, outright genocide was the usual expected remedy. The fleets were also tasked with the secondary mission of exploring the galactic wilderness following the terrible anarchy of the Age of Strife so that new frontiers could be opened for human settlement and resource extraction in formerly virgin regions of the galaxy.

While the Emperor hoped that most human civilisations would willingly accept reunification under the Imperial aegis because of all the benefits interstellar unity offered, He knew that many human worlds would forcefully reject Imperial Compliance. As such, each Expeditionary Fleet was a potent military armada usually under the overall command of a high-ranking officer of the legions or the Imperial Army who bore the rank of Lord Commander and the expedition's fleet elements were commanded by an officer with the rank of Master of the Fleet. Additionally, each of the Emperor's Primarchs was given command of an unusually large Expeditionary Fleet, to which was attached the main body of their Space Marine Legionas well as substantial starship and Imperial Army assets.

These Expeditionary Fleets, which were quite rare since the majority of the Great Crusade's fleets possessed no Astartes contingent at all, usually undertook the major thrusts into completely new areas of the galaxy. Smaller fleets with less combat capacity would then follow in a major fleet's wake, branching off to ensure Imperial Compliance on worlds that presented less human or xenos resistance than those faced by the fleets carrying Astartes complements.

However, the Primarchs of several of the Legions were known at times to split off smaller units of Space Marines from their main fleets to accompany Expeditionary Fleets that were otherwise lacking in Space Marine support. In such situations, the ranking Space Marine officer served as the fleet's Lord Commander since Astartes always assumed command over normal troops in any military situation where they were present during the Great Crusade. What follows here is a list of the few Expeditionary Fleets of the Great Crusade that have been recovered from ancient Imperial records.

## See Also

* The Unification Wars
* The Rangdan War
* The Great Secession