Event · M36
Fifteenth Founding
The Fifteenth Founding is a numbered Chapter-creation event of the Adeptus Astartes, recorded as occurring in the thirty-sixth millennium. It belongs to the long sequence of Foundings by which the Adeptus Terra has replenished and expanded the Space Marine Chapters since the Second Founding divided the surviving Legiones Astartes in the aftermath of the Horus Heresy. Each Founding in this sequence is sanctioned from Terra, where the Adeptus Astartes’ governing councils authorise new Chapter charters, assign gene-seed stock, and confirm recruiting worlds before a Chapter is formally raised. Of the Fifteenth Founding’s own course, little is preserved outside the bare fact of its occurrence. Imperial record-keeping across the ten thousand years since the Heresy is uneven, and many Foundings — the Fifteenth among them — are known chiefly by number rather than by the Chapters, commanders, or campaigns they produced. This contrasts with better-documented Foundings, such as the Second, or the so-called Cursed Foundings of the Thirteenth Black Crusade era, whose Chapters and origins remain traceable. Whether the Fifteenth Founding raised one Chapter or several, and which recruiting worlds or gene-seed lines it drew upon, is not recorded in any surviving Administratum archive accessible to Orrery’s sources. In the present era, no Chapter is confidently attributed to the Fifteenth Founding by name, and its practical legacy is inseparable from the wider, largely anonymous mass of Chapters whose origins are dated only to a Founding number. It stands nonetheless as a fixed point in the Imperium’s founding chronology, anchored to Terra as the seat from which all such charters are granted, and to the broader timeline of Astartes foundings that stretches from the Second Founding to the present.
See where Fifteenth Founding occurred on the galactic map in the 41st Millennium.