The libretto was fabricated on the basis of old legends about Duke Robert the Magnificent of Normandy, the father of William the Conqueror, alleged in some versions to have been the son of the Devil. The librettists padded out this outline with a variety of melodramatic incidents. The plot reflected 'the fantastic legendary elements which fascinated the opera public of 1830', a taste which had evolved from the 1824 Paris production of Carl Maria von Weber's "Der Freischütz" (in its French version "Robin des bois"), which also features a doubtful hero befriended by a demon promising him success.