Samson was born in Wales at the end of the 5th century. He became a monk and was the superior of a monastery in Caldey. He moved to Ireland and in around 548 made the journey to Armorica with several colleagues and founded a monastery there. Later, with the support of the Breton king Judicael, he played a key role in the foundation of the city of Dol and its bishopric. He died in 565 in Dol having nominated Magloire as his successor and his tomb was to become the destination of numerous pilgrims and is included in the Breton Tro Breizh. One of the stained glass window frames in the cathedral depicts Samson sailing for Armorica ("Saint Samson fait voile vers l'Armorique").