Le Roi Arthus is an opera in three acts by French composer Ernest Chausson. It was composed between 1886 and 1895, but first performed on 30 November 1903 after long delays. The musical style is heavily influenced by Richard Wagner, particularly Tristan und Isolde.
Act One Fresh from his defeat of the Saxons, King Arthur praises the fighting prowess of the knights of the Round Table, particularly Lancelot. That night Lancelot meets Arthur's wife Guinevere for an adulterous tryst but the two are spied on by Mordred. Lancelot fights and wounds him.
Act Two Lancelot flees to his castle with Guinevere. He learns that Mordred has survived and revealed the truth to the king. Arthur consults the wizard Merlin who foretells the downfall of the Round Table.Act Three
Arthur pursues Lancelot and gives battle, but Lancelot throws away his weapons and refuses to fight his king. Guinevere, fearing Lancelot's imminent death, strangles herself with her own hair. Arthur forgives the mortally wounded Lancelot. A vessel arrives at the coast to bring the king to the 'Ideal'.