King Arthur pulled the magical sword Excalibur from the stone, proving he was the rightful king of Britain. However, some kings rebelled against his rule. With help from Merlin and the Lady of the Lake, who gave him the magic sword Excalibur, Arthur defeated the rebels in battle. Years later, Arthur's wife Guinevere had an affair with his trusted knight Sir Lancelot. When Arthur found out, he waged war on Lancelot in Brittany. Arthur was badly wounded in his final battle against his treacherous nephew Mordred, and was taken to the Isle of Avalon to die.