Tizca

Tizca, known as the City of Light, was the capital of Prospero and the principal stronghold of the Thousand Sons Legion. Raised under the direction of the primarch Magnus the Red, it served during the Great Crusade and the opening years of the Horus Heresy as both a seat of government and the Legion’s foremost centre of learning, renowned across the Imperium for its towers of glass and silver and for the scale of its accumulated knowledge.

The city was organised around the pursuit and cataloguing of esoteric and psychic lore, reflecting the Thousand Sons’ distinctive character among the Legiones Astartes. Its institutions, including great libraries and archives such as the Athenaeum, housed records gathered from across human space, and its populace included both Legion astropaths and native Prosperine scholars who supported the Thousand Sons’ research into the practice the Legion termed the Enumerations.

Tizca was destroyed during the Battle of Prospero, when Imperial forces under Leman Russ, acting on orders from Terra and supported by the Sisters of Silence and the Legio Custodes, moved against the city to enforce the Council of Nikaea’s ban on sorcery. The resulting devastation ended Tizca’s role as a functioning capital and marked the effective destruction of the Thousand Sons as an Imperial Legion, with survivors departing Prospero under Magnus the Red.