Changes

The 'collective pain' needed to cleanse the Chapter was decided by Dorn to be an Iron Warriors' fortress, the [[The Iron Cage|Iron Cage]]. Perturabo had built the massive fortifications to mock the Imperial Fists, and Dorn led his most die-hard followers in a siege that would last for several weeks. Followers of the Iron Warriors claim that the Imperial Fists suffered a crushing defeat, and that Dorn and his legion would have been wiped out if Perturabo hadn't prolonged Dorn's suffering so long that the Ultramarines managed to intervene.{{Cite This}}

Imperial records indicate otherwise. The Imperial Fists had always been masters of siege craft, and even unprepared and at a disadvantage they fought like lions. Dorn stood as a giant in their midst, his mind clear with purpose after years of doubt and guilt. The Iron Warriors would have had to sacrifice their lives and Primarch to destroy the Imperial Fists, a price they weren't ready to pay. The arrival of the Ultramarines cut the conflict short and the Iron Warriors fled for the [[Eye of Terror]]. The Imperial Fists had suffered staggering losses, but they had proved their loyalty to the Emperor and cleansed themselves of earlier failures.{{Cite This}}