Who was a composer of an opera that Anton van Rooy appeared in?
Anton van Rooy:  He had a voice of enormous proportions and is most remembered for his association with the music dramas of Richard Wagner, especially the "Ring Cycle", "The Mastersingers of Nuremberg" and "Parsifal". Parsifal: Parsifal (WWV 111) is an opera in three acts by German composer Richard Wagner.
i don't know