In response to a commission for a piece to accompany light-and-water shows on the Seine during the "Paris Exposition", in 1937 Messiaen demonstrated his interest in using the ondes Martenot, an electronic instrument, by composing "Fêtes des belles eaux" for an ensemble of six. He included a part for the instrument in several of his subsequent compositions. During this period he composed several multi-movement organ works. He arranged his orchestral suite "L'ascension" ("The Ascension") for organ, replacing the orchestral version's third movement with an entirely new movement, "Transports de joie d'une âme devant la gloire du Christ qui est la sienne" ("Ecstasies of a soul before the glory of Christ which is the soul's own") (). He also wrote the extensive cycles "La Nativité du Seigneur" ("The Nativity of the Lord") and "Les corps glorieux" ("The glorious bodies").