Britu is a son or descendant of Vortigern in various medieval Welsh genealogies. Britu appears as Vortigern’s son and ancestor of the Kings of Powys on the Pillar of Eliseg. He is there said to have been blessed by St. Germanus. In the Harleian MS. 3859 Genealogies (Harleian 3859.23) Britu is son of Catigern (Cattegirn), the son of Catel. Britu is father of Camuir, father of Millo, father of Cinnin.