Lohengrin () is a character in German Arthurian literature. The son of Parzival (Percival), he is a knight of the Holy Grail sent in a boat pulled by swans to rescue a maiden who can never ask his identity. His story, which first appears in Wolfram von Eschenbach's Parzival, is a version of the Knight of the Swan legend known from a variety of medieval sources. Wolfram's story was expanded in two later romances. Richard Wagner's opera Lohengrin of 1848 is based upon the legend. Origin Lohengrin first appears as "Loherangrin", the son of Parzival and Condwiramurs in Wolfram von Eschenbach's Parzival. Wolfram's story is a variation of the Knight of the Swan tale, previously attached to the Crusade cycle of medieval literature. Loherangrin and his twin brother Kardeiz join their parents in Munsalväsche when Parzival becomes the Grail King; Kardeiz later inherits their father's secular lands, and Loherangrin remains in Munsalväsche as a Grail Knight. Members of this order are sent out in secret to provide lords to kingdoms that have lost their protectors and Loherangrin is eventually called to this duty in Brabant, where the duke has died without a male heir. His daughter Elsa fears the kingdom will be lost, but Loherangrin arrives in a boat pulled by a swan and offers to defend her, though he warns her she must never ask his name. He weds the duchess and serves Brabant for years, but one day Elsa asks the forbidden question. He explains his origin and steps back onto his swan boat, never to return. The Knight of the Swan story was previously known from the tales of the ancestry of Godfrey of Bouillon, the first ruler of the Crusader Kingdom of Jerusalem. The story appears in the two versions of the tale Naissance du Chevalier au Cygne, which describes the Swan Knight Elias arriving to defend the dispossessed Duchess of Bouillon. They marry and have a daughter, Ida, who becomes the mother of Godfrey and his brothers. The Knight of the Swan is not the only altered version of a popular story Wolfram uses in his narrative; he makes Prester John the son of his character Feirefiz. Graham Seal suggests that the tale of Lohengrin reworks elements from Northern European folklore. Later versions The story was picked up and expanded in the late 13th-century Lohengrin by a certain "Nouhusius" or "Nouhuwius", who changed the character's