Olivier Messiaen was a French composer, and ornithologist, one of the major composers of the 20th century. His music is rhythmically complex (he was interested in rhythms from ancient Greek and from Hindu sources. He found birdsong fascinating, believed birds to be the greatest musicians, and considered himself as much an ornithologist as a composer. His innovative use of colour, his conception of the relationship between time and music, his use of birdsong makes Messiaen’s music distinctive.