What little is known of Britonia is deduced from its religious history. The British settlements were recognised at the Council of Lugo in 567 and a separate bishopric established. Bishop Mailoc signed the acta of the Second Council of Braga in 572. The British Celtic settlements were quickly absorbed however and their adherence to Celtic Christianity lasted only until the Fourth Council of Toledo in 633 where they accepted Roman Catholic orthodoxy. The see of Britonia existed at least until 830 when the area was attacked by the Moors; it may have continued as as late as the Council of Oviedo in 900. It was finally merged with the see of Oviedo and Mondonedo.
Known bishops of the ecclesia Brittaniensis:
Mailoc (Second Council of Braga, 572)
Metopius (Fourth Council of Toledo, 633)
Sonna (Seventh Council of Toledo, 646)
Susa (Eighth Council of Toledo, 653)
Bela (Third Council of Braga, 675)
Richards, Melville, "Mailoc", Habis, III, 1972, p. 159.
Tovar, António, "Un obispo con nombre británico y los orígenes de la diócesis de Mondoñedo", Habis, III, 1972, pp. 155-158.
Vives, J., Concilios visigóticos e hispano-romanos, Madrid, 1963.
Young, Simon, The Bishops of the early medieval diocese of Britonia (forthcoming).
Young, Simon, "Note on Britones in Thirteenth-century Galicia", Studia Celtica, XXXV (2001), pp. 361-2.
Young, Simon, "The Forgotten Colony", History Today, L, oct. 2000, pp. 5-6.
Young, Simon, "Britonia: Camiños Novos", Noia, 2002. ISBN: 84-95622-58-0. (in Galician)