Event · M31

Battle of Xenobia Principis

The Battle of Xenobia Principis was the first armed conflict between the forces of the Imperium of Man and the Interex, fought late in the Great Crusade, around the year 001.M31, in the city of Xenobia Principis on the Interex frontier world of Xenobia. The engagement followed first contact between the two civilisations at the close of the War on Murder, where the Interex envoy Diath Shehn had met Horus, Warmaster of the Imperium and primarch of the Luna Wolves. On the strength of that meeting, Horus brought the 63rd Expeditionary Fleet to Xenobia on an official visit. Xenobia Principis stood on the shore of a wide ammonia sea, under the command of General Jephta Naud. Imperial visitors were housed in a guest precinct known as the Extranus, and were shown the Hall of Devices, a building that served as both museum and armoury for artefacts and weapons gathered by the Interex. The Interex, a human civilisation long allied with several xenos species in opposition to a power they termed Kaos, regarded their guests with suspicion, fearing the Imperials might themselves be corrupted by that same enemy. While Horus and his officers were occupied in talks with their hosts, unknown intruders broke into the Hall of Devices, seized a Kinebrach blade known as an Anathame, and sabotaged the structure so that it detonated. The Interex took the explosion for a treacherous Imperial strike. Fighting spread rapidly through the streets of the city, with the Luna Wolves engaged by Interex warriors mounted on cybernetic, centaur-like fighting platforms and wielding bows that fired bolts of light capable of piercing power armour. Xenobia Principis was left devastated by the battle, and Horus was evacuated from the planet as the Imperial expedition withdrew. The raid on the Hall of Devices was the work of Erebus, First Chaplain of the Word Bearers, who made off with the Anathame; the blade was later used to wound Horus on the moon of Davin. Convinced that peace with the Interex was no longer possible, Horus committed his forces to war against them, and it was in the aftermath of this first contact that he exercised his right as primarch to rename his Legion, the Luna Wolves becoming the Sons of Horus. The Interex is recorded as having been destroyed in a later Imperial campaign.

See where Battle of Xenobia Principis occurred on the galactic map during the Horus Heresy.

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