The Macharian Heresy was the civil war that broke out across Segmentum Pacificus in the early 41st millennium, after Lord Solar Macharius died and his generals turned on each other. It’s the reason the Imperium’s biggest single conquest in millennia didn’t hold together.
What caused it
Macharius conquered a huge swathe of the galaxy’s western reaches during the Macharian Crusade. When he died around 400.M41, the seven Army Group Generals who’d served under him had no single authority left to answer to.
Their rivalries boiled over into open war. The conquered territories splintered into mini-empires, each run by a former general who’d abandoned their oath to the Imperium and refused the Adeptus Terra’s authority.
Many freshly conquered worlds took the chance to rebel as well, and Space Marine Chapters that had fought in the crusade started settling old scores with each other.
Who fought on which side
The generals split roughly three ways: loyalists, rebels, and one who just ignored everyone.
The loyalists fought to bring the region back under Imperial control. The rebels wanted their own domains. And Cyrus, the greatest scourge of the whole war, became the most dangerous of the breakaway warlords.
- Sejanus (2nd Army Group): stayed loyal to the Imperium.
- Tarka (3rd Army Group): allegiance unknown.
- Lysander (4th Army Group): turned against the Imperium.
- Borgen Crassus (5th Army Group): stayed loyal.
- Arrian (6th Army Group): ignored Imperial authority and became a frenzied warlord, purging worlds he judged blasphemous.
- Cyrus (7th Army Group): turned rebel and earned a reputation as the war’s worst scourge.
The Dark Angels and Cypher
The Dark Angels played a big part in the suppression. Over roughly three decades they put down civil wars and uncovered cults tied to the Alpha Legion and Word Bearers.
Their Ravenwing kept finding traces of Cypher in the chaos, though he always slipped away. The Deathwing did capture several Fallen. The Dark Angels also killed millions on rebel worlds, which is worth remembering when you see the chapter framed as heroic.
Notable battles and how it ended
The Euxcine Incident saw the Minotaurs step into a war between the Doom Eagles and Inceptors, humiliating the Inceptors and nearly wiping them out. The Lythanos Uprisings saw the Dark Angels chase Fallen, only for a run-in with the Space Wolves to let them escape.
The Imperium eventually won. Warmaster Solon led the loyalist forces to victory, though many worlds were destroyed along the way and the region never fully returned to what Macharius had built.
Key facts
- The Macharian Heresy was a civil war in Segmentum Pacificus in the early 41st millennium.
- It started after Lord Solar Macharius died and his seven Army Group Generals fought over his conquests.
- The region splintered into mini-empires ruled by breakaway generals.
- Warmaster Solon led the Imperial loyalists to eventual victory.
- The Dark Angels spent about three decades suppressing the unrest and hunting Fallen.
- Many worlds were destroyed before the war ended.
FAQ
When did the Macharian Heresy happen?
In the early 41st millennium, around 400.M41, shortly after the death of Lord Solar Macharius.
Who won the Macharian Heresy?
The Imperium, under Warmaster Solon. But the victory came at a brutal cost, with many worlds destroyed.
Was Cypher involved?
The Dark Angels found signs of Cypher’s presence during the unrest, though he always escaped them. They did capture several Fallen.