Treaty of Olympus
The Treaty of Olympus was a diplomatic agreement between the Imperium of Man and the Martian Mechanicum binding the former to the latter. The Treaty was signed shortly after the Emperor landed on Mars at the dawn of the Great Crusade, calling for unity and displaying seemingly supernatural powers over machinery, repairing a Knight instantly with a mere touch. Many on Mars began to consider the Emperor the Omnissiah incarnate. As part of the stipulations of the treaty, the Emperor agreed to not interfere in the internal structure of the Mechanicum and allowed them to continue their beliefs in the Omnissiah, the avatar of the Machine God. In exchange, the Cult of the Machine produced and manufactured the wide amount of weapon, ships and other tools for the Imperium for the Great Crusade.
Many members of the Martian Mechanicum, including Fabricator-General Kelbor-Hal, resented the Treaty of Olympus and saw it as a means for the Emperor to subordinate Martian forges. This tension eventually led to the Schism of Mars during the Horus Heresy.