. "The Treachery at Port Maw was a notable military defeat for the Imperium of Mankind during the earliest years of the Horus Heresy and what was later designated the Manachean War. It was by the twin assaults of the Traitors on Hive Illum and the Armada Imperialis Port Majoris of Port Maw that the Manachean War was concluded, marking the end of the powerful star system that had been the heart of the Manachean Commonwealth and the establishment of the first Traitor-held domain in the galaxy. As far as the dire events of Istvaan III and Istvaan V revealed Horus' influence within the Legions of the Legiones Astartes, the Treachery at Port Maw is a testimony to how far Horus' treason ran within every other organisation -- military and civilian -- of the Imperium. To Imperial historians, the \"Treachery at Port Maw\" marks the beginning of a shadow war that has run its course for the last ten millennia, a fifth-columnist's and traitor's war that has since then become the hallmark of another Legion of Traitors: the Alpha Legion."@en . "Treachery at Port Maw"@en . "Port Maw orbit and surface, Aestellica System, Port Maw Sub-sector, Gothic Sector, Segmentum Obscurus"@en . . "44.008"^^ . . . "The Treachery at Port Maw was a notable military defeat for the Imperium of Mankind during the earliest years of the Horus Heresy and what was later designated the Manachean War. It was by the twin assaults of the Traitors on Hive Illum and the Armada Imperialis Port Majoris of Port Maw that the Manachean War was concluded, marking the end of the powerful star system that had been the heart of the Manachean Commonwealth and the establishment of the first Traitor-held domain in the galaxy. As far as the dire events of Istvaan III and Istvaan V revealed Horus' influence within the Legions of the Legiones Astartes, the Treachery at Port Maw is a testimony to how far Horus' treason ran within every other organisation -- military and civilian -- of the Imperium. To Imperial historians, the \"Tre"@en . . . . . . . "Grand Admiral Ospheus LaBray"@en . "Imperial Army Solar Auxilia and Loyalist Armada Imperialis"@en . . . . "unknown"@en . . "Fleet Engagement"@en . . . "Imperial Defeat"@en . . . . . "Sons of Horus, Dark Mechanicus Taghmata Cyclothrathe and Traitor Armada Imperialis"@en . "unknown"@en . "Death of Grand Admiral Ospheus LaBray, capture of Imperial flagship, conquest of Port Maw Port Majoris, conquest of the Manachean Commonwealth. Establishment of a Traitor-dominated pocket-empire, traitorous naval strength greatly augmented for the Battle of Terra"@en . . . . . . .