The Duke of Brittany in the Thomas of England branch of the Tristan legend. He went to war with Tristan’s father, Rivalin or Rouland, who was Morgan’s vassal (the stories differ as to who started the war). The initial war was destructive and a truce was called for a year. At the end of the year, the war resumed and Morgan killed Rivalin.
Tristan, born soon afterwards, was hidden from the vengeful Morgan by Rual or Rohand, his father’s steward. Later, Tristan returned to claim his ancestral land of Parmenie, and he killed Morgan when Morgan refused.
Sir Tristrem gives him three brothers, all killed by Tristan: Morholt, Urgan, and Beliagog.
Urgan the Hairy | The Legend of King Arthur
Tristan | Gottfried von Strassburg, early 13th century
Tristrams Saga ok Ísöndar | 1226
Sir Tristrem | c. 1300