Event · M32
Fourth Founding
The Fourth Founding was one of the periodic Foundings by which the Adeptus Terra raised new Space Marine Chapters after the Horus Heresy. Conducted from Terra in the decades following the reorganisation of the Legiones Astartes into the Codex Astartes system established under the Second Founding, it forms part of the sequence of Chapter-creation edicts through which the Adeptus Terra periodically expanded the Adeptus Astartes to replace losses and answer the Imperium’s continuing wars of reconquest. Surviving records place the Fourth Founding in the early thirty-second millennium, though the precise Chapters it raised and their gene-seed lineages are not consistently attested across later chronicles. The Foundings of this era were sanctioned by the High Lords of Terra in council with senior Chapter Masters, formalising the doctrine that no Chapter should grow beyond a thousand battle-brothers, so that new Chapters rather than swollen Legions absorbed the Imperium’s continuing need for Astartes strength. The Fourth Founding is understood to have drawn on existing Chapters’ gene-seed stocks to seed newly commissioned Chapters, following the precedent set by the Second Founding’s division of the primarchs’ Legions and by the Foundings that came between. Accounts differ on whether it answered a specific crisis or formed part of the Imperium’s routine administrative expansion during the consolidation of its borders in the wake of the Heresy. Later tradition holds that the Fourth Founding’s Chapters, like those raised around it, were dispersed to garrison newly reconquered or vulnerable systems, though few are named with certainty in surviving Administratum archives. Its chief significance lies in its place within the broader sequence of Space Marine Foundings, a history punctuated by later, better-documented episodes such as the Thirteenth and Ultima Foundings, against which the Fourth Founding’s sparser record is typically measured. As with other early Foundings, Terra’s role as the seat of the decision underscores the Adeptus Terra’s continuing authority over the creation and deployment of the Emperor’s Space Marines through the Imperium’s early and middle millennia.
See where Fourth Founding occurred on the galactic map in the 41st Millennium.