Conomor, also known as Conomerus or Conomor the Cursed, was an early medieval ruler of Brittany. His name, which has the Welsh cognate Cynfawr, means "Great Dog", but could also indicate "Sea Dog" in early Brythonic. Conomor was notorious for his cruelty, becoming a legendary villain in Breton culture. He is widely regarded as one of the probable sources for the myth of Bluebeard and possibly also of Tristan's uncle King Mark of Cornwall. The wife-beating giant Cormoran may also retain a garbled folk memory of the same character.

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.