Icon of the Adeptus Mechanicus
The Treaty of Mars, known as the Treaty of Olympus Mons to the Mechanicum, is the formal name given to the binding agreements that regulate the coexistence of the Imperium of Man and the Adeptus Mechanicus since before the start of the Great Crusade in ca. 800.M30. To prevent a wasteful and costly war between the Imperium of Man that was forged on Terra in the wake of the Unification Wars with the techno-empire that had evolved on Mars during the Age of Strife, the Emperor of Mankind proposed a generous compromise that would cement the alliance collaboration of both entities for the next ten millennia. The Treaty of Mars granted political autonomony to the Mechanicum of Mars and its Forge Worlds scattered across the galaxy as well as an exception to the Imperial Truth so that the Cult Mechanicus' adherents could continue to practice their faith. The Imperium would provide Navigators and Astropaths to the Mechanicum so that it could unite its far-flung empire of lost Forge Worlds and continue its sacred Quest for Knowledge across the galaxy. In exchange, the Mechanicum would supply the Imperium of Man with the weapons, starships, materiel and technicians required to initiate the Emperor's Great Crusade to reunite all of the human-settled galaxy beneath the banner of the Imperium. To symbolise the alliance created between Terra and Mars that marked the true birth of the new Imperium, the Emperor changed his personal sigil from one of a lightning bolt to the Aquila, a two-headed eagle whose heads represented the twin foundations of the new human interstellar government -- Terra and Mars, Imperium and Mechanicum.
History
Age of Strife
In times long past, during the Dark Age of Technology, both Terra and Mars maintained separate interstellar empires and collaborated peacefully for the benefit of all Mankind. The onset of the Age of Strife would shatter this amity, as Terra descended into techno-barbarism. On Mars, the situation became even more dire, for the Red Planet's terraformation was still incomplete. Because of the lack of maintenance of the planet's infrastructure during the conflicts that consumed Mars during that period, its atmospheric radiation shields soon disintegrated, allowing deadly solar radiation to destroy the fragile Martian ecosystem and wiping out the sparse, genetically-engineered vegetation which had taken millennia to cultivate. Mars returned to being the red wasteland that had characterised its past. Plagues caused by high radiation levels slew most of the population and many of the survivors devolved into mutants or ghoulish cannibals. Faced with total extinction, a new idea began to spread among the Martian people, a religion that made a faith out of the preservation of the technical knowledge required for survival -- the Cult Mechanicus dedicated to the Machine God.
The devotees of this faith sought out needed technology scattered across the Red Planet that was needed to rebuild temporary radiation shelters. The Cult demanded absolute devotion from its followers, for only by selfless dedication and often personal sacrifices could the needed archeotech be recovered or the planet saved. Under the direction of their Tech-priest leaders, the cultists set about restoring order to their world. They built shelters to protect themselves from the radiation storms, and constructed new oxygen generators and food processing machines to enable them to live beneath the protective shielding.
Yet there were few shelters even for the Tech-priests and none for unbelievers. Marauders and mutant raiders tried to force their way inside the hurriedly constructed edifices. Many of the cultists died defending their shelters and some of these early settlements were destroyed, but the survivors emerged all the stronger and more determined. The Martian people interpreted their survival in the face of tremendous odds as a vindication of their belief in the dogma of the Cult Mechanicus. Their resolve and devotion to the Cult soon became unshakable as the Age of Strife wore on.
While rival warlords battled over the remnants of the once-great civilisation of Terra, the Tech-priests built Mars anew, and the first temples dedicated to the Machine God were erected amidst the crimson sands. The Tech-priests scoured the ruins of Mars for surviving advanced technology which they enshrined within the greatest of the Mechanicum's holy places, the Temple of All Knowledge. In time, the towering forge cities of the Mechanicum's Magi rose into the pink sky, as advanced technology and industry returned to Mars. Now unified under the Cult Mechanicus, the Priesthood of Mars began to dispatch Explorator Fleets across the galaxy and even plundered the surface of war-torn Terra itself when the opportunity presented itself in hopes of discovering lost technologies. Facing resistance to their quest on the Terran surface, the Mechanicum soon became bitter enemies with the techno-barbarians which plagued the devastated Earth. In the meantime, each new world discovered by the Mechanicum's Explorators was colonised and rebuilt in the image of Mars itself, transformed into a planet-wide manufactory known as a Forge World, where industry is the only true religion.
Emperor of Mankind Comes to Mars
When the Emperor of Mankind finished uniting the tribes of Terra during the Unification Wars before 800.M30, He became aware of the existence of the Cult Mechanicus on Mars and the vast, if fractured stellar empire it had colonised. Realising that waging war against Mars and bringing the Cult Mechanicus to heel would be a long and wasteful battle, the Emperor journeyed to Mars in peace and made first contact with the people of the Machine Cult at the summit of Olympus Mons, the greatest mountain of the Red Planet. When the Emperor first emerged from his great voidship surrounded by all the glory and magnificence his psychic abilities could generate, many of the Mechanicum Tech-priests present believed him to be the Omnissiah, the mortal incarnation of the Machine God. The Emperor eventually earned an audience before the Mechanicum's parliament of Magi led by their Fabricator-General Kelbor-Hal. The arrival of the Emperor set off political turmoil across the Red Planet, for having expunged any trace of mutation in their own gene-stock long before, the Martians were at a loss to explain the glory of the immensely powerful psyker who strode amongst them. Capitalising on this, the Emperor spoke of the legendary times long past when Terra and Mars had worked together to form the core of an illustrious interstellar human federation, and told the Martians that He intended to build a new Golden Age for Mankind in the form of His nascent Imperium of Man.
To this end, the Emperor invited the Martians to join Him, proposing them the terms of a generous alliance backed up by the veiled threat that he would unleash His genetically enhanced warriors upon the Red Planet if the Magi refused Him. The Imperial proposal granted political autonomony to the Mechanicum of Mars and its Forge Worlds scattered across the galaxy as well as an exception to the atheistic Imperial Truth so that the Cult Mechanicus' adherents could continue to practice their faith. The Imperium would provide Navigators and Astropaths to the Mechanicum so that it could unite its far-flung empire of lost Forge Worlds and continue its sacred Quest for Knowledge across the galaxy. In exchange, the Mechanicum would supply the Imperium of Man with the weapons, starships, materiel and technicians required to initiate the Emperor's Great Crusade to reunite all of the human-settled galaxy beneath the banner of the Imperium.
The Martians, realising they had much to win by placating the Emperor, and even more to lose if they opposed Him, readily agreed to the terms of the proposed alliance, an agreement aided by the reality that many amongst the Mechanicum already believed Him to be the Omnissiah. Unable to abandon the religion which defined their existence, the Martians proposed a compromise that the Emperor agreed to with some reluctance: He would be presented to the masses of the Cult Mechanicus as the Omnissiah, the living incarnation of the Machine God, the long awaited living repository of knowledge and wisdom who incarnated all of the values of the Cult. Despite being a direct contradiction to the Imperial Truth, the Emperor understood that being presented as the avatar of a God was an acceptable evil in order to secure the Cult Mechanicus' assistance, and that attempting to force the Mechanicum to accept the Imperial Truth could wait until the end of the Great Crusade.
At the same time, the Emperor imposed an exigence of His own upon the Mechanicum. Well aware of the sad story of the Men of Iron and the inherent danger and vulnerability of certain technologies to the corrupting influence of Chaos, He forbade the Mechanicum to pursue certain types of knowledge, foremost amongst those the development or study of Silica Animus; machines that possessed full self-awareness and were totally independent of human control. The Emperor listed a number of machines and technological concepts that could lead to the combination of technology with the sorcery of Chaos, and ordered those subjects to be considered taboo, and not to be researched by the Tech-priests under pain of execution. Since many such forbidden technologies already existed in various Magi's forge cities or lay hidden beneath the sands of Mars, the Emperor ordered Kelbor-Hal to seal all such devices within a special cache that only He or His trusted representatives could open, known as the Vaults of Moravec. The Mechanicum grudgingly acquiesced to this arrangement, but the restraint on the Tech-priests' search for knowledge, even dangerous knowledge, would create resentments that would later reemerge during the Horus Heresy over 200 standard years later.
The terms of this alliance were then formalised in a binding agreement called the Treaty of Mars, known as the Treaty of Olympus Mons to the Tech-priests after the place on the Red Planet where the Emperor had first trod their soil. This treaty would inextricably bind together the Imperium and the Cult Mechanicus for the next ten standard millennia. To symbolise the alliance created between Terra and Mars that marked the true birth of the new Imperium, the Emperor changed his personal sigil from one of a lightning bolt to the Aquila, a two-headed eagle whose heads represented the twin foundations of the new human interstellar government -- Terra and Mars, Imperium and Mechanicum.
Although the alliance was later threatened during the Horus Heresy and the Schism of Mars, it ultimately endured across the millennia. In the late 41st Millennium, the Mechanicum, now known as the Adeptus Mechanicus, is still an almost autonomous entity within the Imperium, spared most of the attention of the Adeptus Ministorum and Inquisition by the dictates of this ancient treaty which laid the very foundation of the Imperium of Man.
Sources
- Imperial Armour - The Horus Heresy - Book One: Betrayal, pp. 17-19
- Titan Legions Rulebook (1st Edition), pp. 9-11
- Warhammer 40,000: Rulebook (6th Edition), pg. 402
- Warhammer 40,000: Rulebook (4th Edition), pp. 98-110
- White Dwarf 178 (UK) "The Titan Legions" by Rick Priestley
- Mechanicum (Novel) by Graham McNeill, pp. 29, 228, 317