St. Samson is counted among the seven founding saints of Brittany. He was born in Wales, his father being the son of Amon of Demetia and Anne of Gwent, daughter of Meurig, king of Glamorgan and Gwent.
Early in life his education was entrusted to St. Illtud, the abbot of Llandtwit Fawr.
Seeking an even more austere life than this school provided, Samson moved to the island monastery of Caldey where he became a model of virtue. There, he succeeded St. Pyr as abbot.
Later, his father Amon and an uncle joined him in the monastic life. At one point he made a visit to Ireland, and on his return, with his father and uncle retired to a hermittage.
But his peace did not last. He was again made abbot, and was subsequently consecrated bishop by St. Dubricius. After a vision instructing him to travel beyond the sea, he sailed for Cornwall, converting a number of idol worshipers by miraculously restoring a boy who had been thrown by a horse.
He founded a couple of churches, after which he sailed for Brittany possibly visiting the Scilly Islands, one of which is named after him.
In Brittany he traveled extensively preaching and teaching, and working many miracles. A town in Guernsey bears his name. He founded two monasteries, one in Dol and another in Normandy. While visiting Paris he attracted the notice of King Childebert who is said to have appointed him bishop of Dol. Samson died peacefully among his monks in the year 565.