Son of Constantine and father of Arthur’s warriors Geraint, Ermid, and Dywel.

Erbin ruled a Cornish kingdom, which he had to turn over to his son Geraint when he became ill. Geraint returned rule of the land briefly to Erbin when Geraint left for a series of adventures, but he eventually came back and took the crown from his aging and grateful father. His counterpart in the French romances, as Erec’s father, is Lac.