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The Grail was sought by the knights of King Arthur in several medieval romances, the earliest of which was the late-twelfth-century Perceval by Chretien de Troyes. The quest for the Grail, which can only be found by a hero free from sin, is treated at length in the Morte d’Arthur (circa 1469) of Sir Thomas Malory and in Wolfram von Eschenbach's epic, Parzifal (circa 1210), which inspired the German composer Richard Wagner's opera Parsifal (1877-82). See Glastonbury, Templars and Merlin.