However, in the Post-Vulgate Palamedes' conversion to Christianity during the Grail Quest allows him release from his worldly entanglements, and Percival and Galahad help him trap the beast in a lake, where he finally slays it. Malory has Palamedes and Safir joining Lancelot after the great knight's affair with Queen Guinevere is exposed; the brothers eventually accompany Lancelot to France, where Palamedes is made Duke of Provence. According to the Post-Vulgate, Sir Gawain, once a friend to Sir Palamedes, was obliged to kill him after the Grail Quest because Palamedes had killed King Mark, who, it was said, had killed Tristan; King Mark was provoked by the sinister Mordred to kill Tristan with Palamedes' spear.[1]