Event · M31
Tizca
Tizca was the capital city of Prospero and the seat of the Thousand Sons, destroyed by the Space Wolves in the Burning of Prospero. The city, often called the City of Light, was the principal centre of learning of Magnus the Red’s Legion and the site of the Pyramid of Photep and its great libraries. The assault on it occurred in the early years of the Horus Heresy, in the wake of the Council of Nikaea, which had censured the Legion’s use of sorcery. Magnus was later recorded as having attempted a psychic warning to the Emperor about Horus; the transmission is held to have disrupted the Emperor’s work in the Webway and to have been treated as defiance. Accounts differ on how far Horus’s manipulations shaped the decision to send Leman Russ and the Space Wolves to Prospero, but the Legion was judged to be in violation of the Emperor’s edicts. The Space Wolves, accompanied by agents of the Imperium such as Adeptus Custodes and Sisters of Silence, descended on Prospero to bring Magnus to account, and the fighting reached the streets and pyramids of Tizca. The Thousand Sons, whose officers included Ahzek Ahriman and Amon, were unprepared for a war against fellow Legions and were overwhelmed by the force and ferocity of the invaders. The city’s libraries and towers burned, and the planet’s surface was devastated over the course of the campaign. Magnus is recorded as having been drawn from the Emperor’s judgement by the intervention of the Warp, a rescue later tradition associates with Tzeentch, and he abandoned the world. The fall of Tizca effectively ended the Thousand Sons as a Legion of Prospero. Survivors withdrew to the Eye of Terror, where Magnus later established the Planet of the Sorcerers, and the Legion aligned itself with the Traitors. Ahriman’s later Rubric, which transformed most of the surviving Astartes into dust-bound constructs, is traditionally placed in the aftermath of this destruction. On the Orrery map, Tizca anchors the Burning of Prospero to Prospero itself; on the timeline it stands as a pivotal beat between the Council of Nikaea and the wider outbreak of the Heresy, alongside contemporaries such as Isstvan III and the rise of Horus as Warmaster.
See where Tizca occurred on the galactic map during the Horus Heresy.