The original source for Die Fledermaus is a farce by German playwright Julius Roderich Benedix (1811–1873), Das Gefängnis (The Prison). Another source is a French vaudeville play, Le réveillon, by Henri Meilhac and Ludovic Halévy. This was first translated by Karl Haffner into a non-musical play to be produced in Vienna. However, the peculiarly French custom of the réveillon (a New Year's Eve supper party) caused problems, which were solved by the decision to adapt the play as a libretto for Johann Strauss, with the réveillon replaced by a Viennese ball. At this point Haffner's translation was handed over for adaptation to Richard Genée, who subsequently claimed not only that he had made a fresh translation from scratch but that he had never even met Haffner.