Who was a composer of an opera that Anton van Rooy appeared in?
Anton van Rooy: Anton van Rooy (1 January 1870 – 28 November 1932) was a Dutch bass-baritone. 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".
i don't know