Olivier Messiaen (; December 10, 1908 – April 27, 1992) was a French composer,
organist and
ornithologist, one of the major composers of the 20th century. His music is rhythmically complex; harmonically and
melodically it often uses
modes of limited transposition, which he abstracted from his early compositions and improvisations. Messiaen also drew on his Roman Catholic faith for his pieces.