Two years after "Visions de l'Amen", Messiaen composed the song cycle "Harawi", the first of three works inspired by the legend of Tristan and Isolde. The second of these works about human (as opposed to divine) love was the result of a commission from Serge Koussevitzky. Messiaen stated that the commission did not specify the length of the work or the size of the orchestra. This was the ten-movement "Turangalîla-Symphonie". It is not a conventional symphony, but rather an extended meditation on the joy of human union and love. It does not contain the sexual guilt inherent in Richard Wagner's "Tristan und Isolde" because Messiaen believed that sexual love is a divine gift. The third piece inspired by the "Tristan" myth was "Cinq rechants" for twelve unaccompanied singers, described by Messiaen as influenced by the alba of the troubadours. Messiaen visited the United States in 1949, where his music was conducted by Koussevitsky and Leopold Stokowski. His "Turangalîla-Symphonie" was first performed in the US in 1949, conducted by Leonard Bernstein.