Tristram (Tristan) , one of the Knights of the Round Table, was the nephew of King Mark of Cornwall. His mother died after giving birth to him and he was brought up at the court of King Mark, and became a skilful hunter and harper. Tristram fought and killed Sir Marhaus, the brother of queen of Ireland and he himself was wounded. He was sent to Ireland to be cured of his wound. Owing to his skill with the harp the king of Ireland kindly received him and told his daughter Isoud (Isolt or Isolde) to take care of him. Tristram and Isoud fell in love. When the queen discovered the guest was the knight who had killed her brother, Tristram had to return to Cornwall.

After a time, King Mark, who felt jealous of Tristram and wanted to get rid of him, sent him to Ireland to ask for him the hand of Isoud. Tristram, having killed a poisonous dragon for Ireland, asked the king to allow his daughter to marry King Mark as a reward for his service. Isoud and her maid Bragwaine returned with Tristram by ship to Cornwall. Bragwaine had received from Isoud’s mother a magic liquid to be given to King Mark. The liquid could make the man and woman who drank it love each other for the rest of their lives. On the voyage Tristram and Isoud found the liquid and drank it without knowing its effect. Mark and Isoud were married, but the love affair between Tristram and Isoud continued until Mark discovered it. Tristram had to leave Mark’s court.

While fighting in Brittany, Tristram fell in love with another Isoud (Isou the White Hand) and married her. Later, Tristram was wounded by a poisoned arrow. Feeling that he was dying, he sent for Isoud of Ireland to come to cure him. If she came, the ship that brought her was to set a white sail, if not, a black sail. When the ship returned, however, his jealous wife told him the sail was black. In despair, Tristram turned his face to the wall and died. Isoud of Ireland found her lover died, lay down by his side and also died.