Which philosopher’s ideas inspired Also sprach Zarathustra?

The symphonic poem Also sprach Zarathustra (1896) by the German composer Richard Strauss was inspired by the philosophical ideas of Friedrich Nietzsche.2

Specifically, the work serves as a musical homage to Nietzsche’s influential treatise, Thus Spake Zarathustra, which introduced key concepts of his mature philosophy, such as the Übermensch ("superman") and the "will to power". While the composition is often associated with these philosophical themes, Strauss described the piece as a concerto for orchestra that illustrates and contrasts the entities of man and nature through opposing tonalities.12