The viola often plays the "inner voices" in string quartets and symphonic writing, and it is more likely than the first violin to play accompaniment parts. The viola occasionally plays a major, soloistic role in orchestral music. Examples include the symphonic poem, "Don Quixote", by Richard Strauss, and the symphony/concerto, "Harold en Italie", by Hector Berlioz. In the earlier part of the 20th century, more composers began to write for the viola, encouraged by the emergence of specialized soloists such as Lionel Tertis and William Primrose. English composers Arthur Bliss, York Bowen, Benjamin Dale, Frank Bridge, Benjamin Britten, Rebecca Clarke and Ralph Vaughan Williams all wrote substantial chamber and concert works. Many of these pieces were commissioned by, or written for Lionel Tertis. William Walton, Bohuslav Martinů, Tōru Takemitsu, Tibor Serly, Alfred Schnittke, and Béla Bartók have written well-known viola concertos. The concerti by Béla Bartók, Paul Hindemith, Carl Stamitz, Georg Philipp Telemann, and William Walton are considered major works of the viola repertoire. Paul Hindemith, who was a violist, wrote a substantial amount of music for viola, including the concerto, "Der Schwanendreher".