Original: Ives had composed two symphonies, but it is with The Unanswered Question (1906), written for the highly unusual combination of trumpet, four flutes, and string orchestra, that he established the mature sonic world that became his signature style.
Simplified: Perhaps the piece which is most often heard today is the short fanfare The Unanswered Question (1908), written for the very unusual combination of trumpet, four flutes, and string orchestra.