Event · M41–M42
Indomitus Crusade Fleet Primus
Indomitus Crusade Fleet Primus was the first and principal fleet of the Indomitus Crusade, launched from Terra under Roboute Guilliman at the end of M41. It arose from the crisis that followed the opening of the Great Rift, the Cicatrix Maledictum, which divided the Imperium into a lightless northern half and a beleaguered southern half and cut the Astronomican’s reach across much of the galaxy. Guilliman, returned to active command after his long stasis and the work of Belisarius Cawl on Mars, was named Lord Commander of the Imperium and resolved to recover isolated worlds, reinforce the Imperium’s fractured defences and gather its scattered strength. Accounts describe the Crusade as divided into several fleets, of which Primus was the one he led in person. The fleet was assembled around the Ultramarines and their Successor Chapters, together with Imperial Navy squadrons, Adeptus Mechanicus contingents and the first large formations of Primaris Space Marines produced by Cawl. From Terra, the seat of the High Lords, the Lord Commander’s fleet is recorded as turning towards Ultramar, the Ultramarines’ realm in the southern Imperium, where the Rift’s effects and the assaults of Chaos and xenos forces had left the Five Hundred Worlds under heavy strain. There the fleet’s campaigns overlapped with the Plague Wars, in which forces of Nurgle under Mortarion contested Ultramar and neighbouring systems. Fleet Primus therefore stands at the junction of the Indomitus Crusade’s launch, the turn of the millennium and the opening of the Era Indomitus. In the aftermath, Fleet Primus became the model for the wider Crusade and the rallying point for Guilliman’s later efforts to reorganise the Imperium’s defence. Its Primaris reinforcements altered the strength of many Chapters, and its return to Ultramar restored a major southern bastion, though the war there continued into M42. Details of individual engagements, force compositions and the fate of specific vessels are recorded unevenly, and accounts differ on some of them. On Orrery the event links Terra, the Ultramarines, Guilliman and the Indomitus Crusade timeline, and it is best read alongside the Plague Wars and the other Indomitus fleets.
See where Indomitus Crusade Fleet Primus occurred on the galactic map in the 41st Millennium.