Sibelius also had a love of nature, and much of his creative energy was devoted to setting legend and landscape to music. Sibelius became a major force in Finnish music with the Kullervo Symphony of 1891/2, which drew on mythology for inspiration, and the following year he composed En Saga and the Karelia Suite. String trio Composed by Jean Sibelius (1865-1957). Andante Festivo [ˌ a n ˈ d a n. t e ˌ f ɛ s ˈ t i. v o] is a single-movement composition by Jean Sibelius, originally scored for string quartet in 1922. In 1938, the composer rescored the piece for string orchestra and timpani. String trio Composed by Jean Sibelius (1865-1957).