Traditions of Carannog, a Welsh saint of about the year 550, appear in his vita prima written in the twelfth century and surviving in a copy of the thirteenth (his vita secunda, a mere fragment, is not discussed here). The vita prima is best known for what it says on Arthur. Carannog leaves Wales, encounters King Arthur in south-west Britain, eventually gains his support, and is given lands near Arthur’s stronghold of Din Draithou. The location of that fortress has been obscure, but it must have been famous, because it figures in the ninth-century Historia Brittonum, as also the Glossary of Cormac (d. 908), bishop-king of Cashel in south-west Ireland.