The first half of 20th century saw a split between German and Austrian
music. Arnold Schoenberg moved
along an increasingly avant-garde path, pioneering atonal music in 1909
and twelve tone music in 1923. Composers in Berlin took a more
populist route, from the cabaret-like socialist operas of Kurt Weill.
Many composers emigrated to the United States when the Nazi Party came
to power, including Schoenberg, Hindemith, and Erich. During this period, the
Nazi Party embarked on a campaign to rid Germany of so-called degenerate art,
which became a catch-all phrase that included music with any link to Jews,
Communists, jazz, and anything else thought to be dangerous. Some figures such
as Karl Amadeus Hartmann remained defiantly in Germany during the years of Nazi
dominance, continually watchful of how their output might be interpreted by the
authorities.