Samson of Dol was a Welsh saint, who is also counted among the seven founder saints of Brittany with Pol Aurelian, Tugdual or Tudwal, Brieuc, Malo, Patern (Paternus) and Corentin. Born in southern Wales, he died in Dol-de-Bretagne, a small town in north Brittany.

Illtud, also known as Illtud Farchog or Illtud the Knight, is venerated as the abbot teacher of the divinity school, Bangor Illtyd, located in Llanilltud Fawr in Glamorgan, Wales. He founded the monastery and college in the 6th century, and the school is believed to be Britain's earliest centre of learning. At its height, it had over a thousand pupils and schooled many of the great saints of the age, such as David, Samson of Dol, and the historian Gildas.