Oliver (in Italian: Uliviero or Oliviero), sometimes referred to as Olivier de Vienne or de Gennes, is a fictional knight in the Matter of France chansons de geste, especially the French epic The Song of Roland. In the tradition, he was Roland's closest friend, advisor, and confidant, one of Charlemagne's twelve peers and brother of Aude, Roland's betrothed; and he dies at the Battle of Roncevaux Pass with Roland. Some critics have linked his name to the olive tree, a biblical symbol of divine wisdom.