Paul Hindemith (1895-1963) studied as a violinist and composer (with Mendelssohn and Sekles) at the Hoch Conservatory in Frankfurt (1908-17) and made an early reputation through his chamber music and expressionist operas. But then he turned to neo-classicism in his Kammermusik no.1, the first of seven such works imitating the Baroque concerto while using an expanded tonal harmony and distinctively modern elements, notably jazz. Each uses a different mixed chamber orchestra, suited to music of linear counterpoint and, in the fast movements, strongly pulsed rhythm.
During this early period Hindemith lived as a performer: he was leader of the Frankfurt Opera orchestra (1915-23, with a break for army service), and he played the viola in the Amar-Hindemith Quartet (1921-9) as well as in the first performance of Walton's Viola Concerto (1929). Much of his chamber music was written in 1917-24, including four of his six quartets and numerous sonatas, and he was also involved in promoting chamber music through his administrative work for the Donaueschingen Festival (1923-30). However, he also found time to compose abundantly in other genres; including lieder (Das Marienleben, to Rilke poems), music for newly invented mechanical instruments, music for schoolchildren and amateurs, and opera (Cardillac, a fantasy melodrama in neo-classical forms). In addition, from 1927 he taught at the Berlin Musikhochschule.
His concern with so many branches of music sprang from a sense of ethical responsibility that inevitably became more acute with the rise of the Nazis. With the beginning of the 1930s he moved from chamber ensembles to the more public domain of the symphony orchestra, and at the same time his music became harmonically smoother and less intensively contrapuntal. Then in the opera Mathis der Maler (preceded by a symphony of orchestral excerpts) he dramatized the dilemma of the artist in society, eventually opposing Brechtian engagement and insisting on a greater responsibility to art. Nevertheless, his music fell under official disapproval, and in 1938 he left for Switzerland, where Mathis had its first performance. He moved on to the USA and taught at Yale (1940-53), but spent his last decade back in Switzerland.
His later music is in the style that he had established in the early 1930s and that he had theoretically expounded in his Craft of Musical Composition (1937-9), where he ranks scale degrees and harmonic intervals in order from most consonant (tonic, octave) to most dissonant (augmented 4th, tritone), providing a justification for the primacy of the triad. His large output of the later 1930s and 1940s includes concertos (for violin, cello, piano, clarinet and horn) and other orchestral works, as well as sonatas for most of the standard instruments. His search for an all-encompassing, all-explaining harmony also found expression in his Kepler opera Die Harmonie der Welt.