Event · M40
Twenty-Fifth Founding
The Twenty-Fifth Founding is one of the numbered Foundings by which the Adeptus Terra has raised new Chapters of Space Marines across the Imperium’s history. Convened from Terra, seat of the High Lords and the Adeptus Terra, each Founding formalises the creation of fresh Chapters when losses, expansion, or strategic need demand it, following the pattern set by the Second Founding that first divided the nine Loyalist Legions after the Horus Heresy. The Twenty-Fifth Founding belongs to this long administrative and martial tradition, one of dozens of such acts recorded across ten thousand years of Imperial rule, though it precedes the more recent Primaris Foundings such as the Ultima Founding. Its particulars are recorded with less certainty than those of earlier, better-documented Foundings. As with other Foundings drawn along Codex Astartes lines, new Chapters raised in this period would have received gene-seed cultivated from an established First Founding Chapter, their commanders and doctrines shaped by the Adeptus Terra’s oversight and the Fabricator-General’s allocation of Mechanicus resources. Accounts differ on exactly which Chapters trace their founding to this act rather than to the Foundings immediately before or after it, a common difficulty given the Imperium’s uneven record-keeping across the affected millennia and the tendency of Chapters to guard their own origins closely. What is clear is that the Twenty-Fifth Founding forms one link in the unbroken chain connecting the Second Founding to the present era, a chain that stretches to the Ultima Founding and the rise of the Primaris Space Marines. Any Chapter tracing its lineage to this Founding remains bound to the Adeptus Astartes as a whole and, through it, to Terra as the administrative heart from which every Founding is ultimately sanctioned. The Twenty-Fifth Founding is thus remembered less for a single deed than for its place in the sequence of Chapter creation that has sustained the Imperium’s martial strength since the Heresy.
See where Twenty-Fifth Founding occurred on the galactic map in the 41st Millennium.