 His work as an organist led him to write "Variations on "America"" in 1891, which he premiered at a recital celebrating the Fourth of July.In 1906, Ives composed the first radical musical work of the twentieth century, "Central Park in the Dark".He composed two symphonies, as well as "The Unanswered Question" (1908), written for the unusual combination of trumpet, four flutes, and string quartet.