For 10 points, identify this greatest Knight of the Round Table, who lost King Arthur's trust by having an affair with his wife Guinevere.
This figure successfully negotiated the surrender of Galehaut and fought the Copper Knight at the castle of Dolorous Guard, after which he found his true name under a metal slab and renamed the castle Joyous Guard. He crossed the Sword Bridge on his way to defeat Meleagant, an adventure on which he gained the appellation "Knight of the Cart." He is the son of King Ban and Elaine of Benoic, and with Elaine of Carbonek, the daughter of the Fisher King, he fathers Galahad. For 10 points, identify this greatest Knight of the Round Table, who lost King Arthur's trust by having an affair with his wife Guinevere.
This figure successfully negotiated the surrender of Galehaut and fought the Copper Knight at the castle of Dolorous Guard, after which he found his true name under a metal slab and renamed the castle Joyous Guard.
Sir {Lancelot} du Lac [accept {Launcelot}]