Category:Twenty Third Founding

The 23rd Founding, also known as the Sentinel Founding, occurred in the late 37th and early 38th Millennia to replenish the Imperium’s depleted Space Marine forces. It followed a period of immense turmoil, including the Age of Apostasy and the disastrous 21st “Cursed” Founding.

During this era, at least 57 Chapters were lost, destroyed, or turned Renegade, prompting the High Lords of Terra to authorize a new wave of Space Marine creation. The 23rd Founding focused on stability and strategic deployment, using the most reliable gene-seed stocks available. Several Chapters were designed for perpetual crusading roles, tasked with reclaiming and defending vulnerable regions of the Imperium. Notable examples include the Marines Errant, descended from the Eagle Warriors (and ultimately the Ultramarines), and the Star Phantoms, whose origins remain mysterious but are speculated to involve Dark Angels gene-seed — a claim both Chapters deny.

Other Chapters from this Founding include the Iron Lords, created to contain the xenos Barghesi in the Grendl Stars; the Imperial Harbingers, from the dark world of Birmingham; and the Steel Cobras, who tragically fell to Chaos after being persecuted by the Ecclesiarchy for their totemic worship of the Emperor. The full scope of the Sentinel Founding remains obscured, but it is believed that even the Celestial Lions may have emerged from this wave of gene-line expansion