A crucial figure in the transition between the Classical and Romantic eras in Western art music, he remains one of the most famous and influential of all composers. His best-known compositions include 9 symphonies, 5 piano concertos, 1 violin concerto, 32 piano sonatas, 16 string quartets, his great Mass the Missa solemnis, and one opera, Fidelio. By 1796, he had begun to suffer from tinnitus and was losing his hearing.