Event · M41
Boros Gate
The Boros Gate is a site on Macragge, homeworld of the Ultramarines, recorded as a point of conflict with the Black Legion in the forty-first millennium. Macragge is the capital world of Ultramar and the birthplace of Roboute Guilliman, so any assault upon it carries strategic and symbolic weight for both the Chapter and its enemies. The Black Legion, the warband led by Ezekyle Abaddon, holds the Ultramarines and the legacy of the Thirteenth Legion among its most persistent adversaries. That enmity is the usual context given for hostile landings on Macragge, and it frames the engagement at the gate. The principal participants are the Ultramarines, the First Founding Chapter descended from Guilliman’s Legion, and Black Legion forces drawn from the wider warband and its allies. The Ultramarines defend Macragge from fortified positions under the command of the Chapter Master, who in this era is Marneus Calgar. Accounts of the gate’s course are recorded only in outline. The fighting is generally described as a contest over an approach to the Ultramarines’ defensive works, in which the defenders sought to keep the attackers from advancing further into the planet’s interior. The precise order of battle, the dates within the millennium and the sequence of assaults are not settled in the material reflected on Orrery, and this entry does not supply them. In the timeline, the Boros Gate belongs to the long series of encounters between Chaos and Ultramar, alongside other assaults on the Ultramarines’ worlds. Its aftermath is understood in terms of the Chapter’s continued hold on Macragge, which remains the seat of its authority. On the map, the event is anchored to Macragge and can be read with the planet’s other defensive and historical sites. Readers should treat this entry as an account of the confrontation’s broad shape and setting rather than a detailed campaign history.
See where Boros Gate occurred on the galactic map in the 41st Millennium.