The Night of a Thousand Rebellions was a lamentable event that occurred across large portions of the Segmentum Pacificus when it was subjected to system-wide planetary insurrections and rebellions that occurred in 992999.M41.
Carefully seeded rebellions sown across Segmentum Pacificus all bear their bloody fruit upon the same night. Uprisings and discord strike at the heart of hundred of worlds, including the supposedly secure Imperial strongholds of Enceladus, Darkhold and Minisotira. Even the home world of the Lions Defiant Space Marine Chapter is lost to anarchy caused by secret cults and frenetic agitators. Contact was lost with large swathes of the segmentum as the Heretic Astartes move in, revealing themselves as the orchestrators of the insurrection, to take advantage of the discord and disorder that reigned across the segmentum.
- Codex: Chaos Space Marines (6th Edition), "The Long War," pg. 25
- Warhammer 40,000: Rulebook (6th Edition), "Age of the Imperium - The Time of Ending," pg. 177