Duke of Cornwall and husband of Arthur's mother, Ygerna. First appearing in Geoffrey of Monmouth, we are told of King Uther's lust for the duke's wife. The duke barricades Ygerna in the fortress of Tintagel as he goes to the field to do battle with Uther. However, Merlin has transformed Uther into the likeness of the Duke and the king walks into the fortress and has sex with Ygerna as her husband dies on the battlefield. Arthur was conceived at this union. Gorlois is also the father of Arthur's half-sisters Morgause, Elaine and Morgan.