St Samson was born in 485AD to Amon of Dyfed and Anna of Gwynedd, while still a child he was dedicated to God. He was brought up by St. Illtyd in the monastery of Llantwit Major. He joined the Celtic Monastic community on Caldey Island where he became Abbot.

St Samson built a monastery near Dol in France, he was nominated Bishop of Dol by King Childebert. It was at Dol he died in 565AD and it is there where he is buried.