The Treaty of Olympus is the deal struck between the Emperor and the Martian Mechanicum in 739.M30, and it’s the reason the Imperium could arm the Great Crusade at all. Without it, there’s no Aquila, no joint war machine, and probably no Imperium as we know it.
What the treaty actually was
It’s a diplomatic agreement between the Imperium of Man and the Mechanicum of Mars, signed shortly after the Emperor landed at Olympus Mons. The Mechanicum became a client-state of the Imperium, though it kept enormous internal freedom.
Sources also call it the Treaty of Mars, and the Adeptus Mechanicus remembers it as the Treaty of Olympus Mons. Same event, different names depending on who’s telling it.
The deal avoided a war in the Sol System that would’ve been ruinous for both sides. The Emperor needed industry. Mars needed protection and resources it couldn’t easily get on its own.
Why Mars said yes
The Emperor arrived on Mars showing off knowledge and power that stunned the Tech-Priests watching. He repaired a Knight with a touch, and that display convinced many of them he was the Omnissiah, the Machine God made flesh.
That belief is baked into Cult Mechanicus dogma to this day. It also gave the Emperor leverage he used to shape what the Mechanicum could and couldn’t research.
- The Imperium wouldn’t interfere with Mechanicum internal structure or the Cult Mechanicus.
- Mars got six full Navis Nobilite Houses, plus access to Astropaths and Navigators.
- Any new technological discovery fell under Mechanicum jurisdiction.
- In return, Mars produced the weapons, ships, and supplies that fuelled the Great Crusade.
The catch: hereteknika bans
The treaty didn’t just hand out favours. It banned whole fields of research, and those bans became the foundation of what the Mechanicum calls the Orders of High Heretek. Artificial intelligence, deep study of the warp, and manipulation of human gene-code all went on the forbidden list.
Some of those restrictions tied directly to the Emperor’s own projects, including the Primarchs and the Custodes. Forge worlds locked away heretical knowledge, and chasing it further counted as blasphemy against the Machine God.
Not every Martian accepted the Emperor as the Omnissiah. Dissenters existed from the start, and that friction never fully went away.
What it left behind
The treaty is often credited with the Imperium adopting the two-headed Aquila as its symbol, a nod to the alliance between Terra and Mars.
It’s also the template for how the Imperium deals with powerful institutions: give them room to run themselves, then lean on them when you need something built. That arrangement outlived the Great Crusade and shaped the Adeptus Mechanicus for ten thousand years.
Key facts
- Signed in 739.M30 between the Emperor and the Martian Mechanicum.
- Also called the Treaty of Mars, or Treaty of Olympus Mons by the Mechanicum.
- Made the Mechanicum a client-state of the Imperium while keeping its internal autonomy.
- Gave Mars six Navis Nobilite Houses and access to Navigators and Astropaths.
- Banned AI, deep warp study, and human gene-code manipulation, laying the groundwork for High Heretek.
- Credited with the Imperium adopting the two-headed Aquila.
FAQ
When was the Treaty of Olympus signed?
In 739.M30, shortly after the Emperor landed at Olympus Mons on Mars at the dawn of the Great Crusade.
Is the Treaty of Olympus the same as the Treaty of Mars?
Yes. It’s the same agreement, known by different names. The Mechanicum calls it the Treaty of Olympus Mons.
Why did the Emperor make the treaty?
The Unification Wars left the Imperium short on supplies and industry. Mars had both, and a deal was cheaper than a war in the Sol System.
What did the Mechanicum get out of it?
Autonomy over its internal affairs and religion, six Navis Nobilite Houses, Navigator and Astropath support, and jurisdiction over new technology.