Pabo Post Prydain was a sub-Roman monarch from the Old North who is remembered as a saint. Known as the Pillar of Britain due to his bravery against the Picts and Scots, he reportedly fled his northern kingdom around 460 and established himself in Anglesey. Historical genealogies link him to several royal and saintly lineages, including his grandsons Deiniol, Asaph, and Tysilio. Tradition suggests that after his reign, he entered a life of religious seclusion, eventually becoming the founder of a church in the area where he was buried.