Event · M31

Purge of Olympia

The Purge of Olympia was the destruction of the Iron Warriors’ home world by its own primarch, Perturabo, shortly before the Horus Heresy, in response to a revolt against Imperial rule. After the death of Dammekos, the former Tyrant of Lochos, the city-states of Olympia resumed the rivalries and intrigues that Perturabo’s conquest had suppressed, and the planet rose against the Legion that governed it. One account holds that the rebellion was covertly engineered by the Word Bearers. The news reached Perturabo in the aftermath of the costly Sak’trada Deeps Campaign against the Hrud. Returning to Olympia with the Iron Warriors, he demanded that the Olympians carry out a decimation upon themselves, putting one in every ten to death, or face extermination and enslavement. Many cities refused, and Perturabo reduced them one after another, street by street, overrunning the fortresses he had himself built and sparing no one; Iron Warriors who refused to take part were killed by their brothers, though a few escaped the planet and later fought against their former Legion. While storming the palace of Lochos he strangled his foster sister Calliphone after she blamed him for the ruin of their world. By the end some five million Olympians were dead and the survivors had been enslaved, and great pyres burned across the planet. In the aftermath the Legion recognised that it had turned from fighting the Hrud to committing genocide upon its own people, and Perturabo concluded that the Emperor would never forgive him. Horus, by contrast, praised his decisiveness, and Perturabo swore loyalty to the Warmaster, a bond that carried the Iron Warriors into the Heresy. Olympia was later besieged by the Imperial Fists and Ultramarines after Horus’s death, in a separate siege that ended with the planet laid waste by the Iron Warriors’ own missiles.

See where Purge of Olympia occurred on the galactic map during the Horus Heresy.

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