After completing several movements of his Second Wind Sonata in 1944, Richard Strauss turned his attention to composing a string work. Through Karl Böhm, he received a request from Paul Sacher for a new composition for Sacher's Collegium Musicum in Zurich. In a letter, Strauss explained that he was already working on an Adagio for about eleven solo strings, but expressed doubts about its completion, as concerns for his family in Vienna and the strain of the war were hindering his composing. Alongside other arrangements, Strauss resumed work on the string composition in early 1945, which he now titled Metamorphosen. The work was initially completed in a version for eleven strings, but was later expanded to include 23 solo strings and finished in April 1945.
The first septet version did not surface in Switzerland until 1990 and was premiered in Garmisch in 1994. The premiere of the 23-part version took place in Zurich in January 1946, conducted by Sacher. Although Metamorphosen contains no direct quotations from Wagner, its thematic structure is reminiscent of him. Strauss is said to have intended to create monuments to German culture between 1943 and 1945. The composition begins with a seemingly tragic introduction, followed by an exposition and a freely structured middle section in which the main theme is varied. The main motif is taken up again in the coda, and the work concludes with a moving duet for several solo instruments.
The Piano Quartet, composed years earlier, documents Strauss's compositional development. While it bears traces of Brahms's influence, it clearly reveals Strauss's individual artistic language. Capriccio, Strauss's last opera, was composed in 1940/41 and begins with a string sextet that may have served as a source of inspiration for Metamorphosen. The opera premiered in Munich in 1942, but the sextet had already been performed earlier at a private event at the home of Baldur von Schirach – as thanks for the protection of Strauss's family.