Olivier Eugène Prosper Charles Messiaen (UK: /ˈmɛsiæ̃/, US: /mɛˈsjæ̃, meɪˈsjæ̃, mɛˈsjɒ̃/, French: ; 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 he employs a system he called modes of limited transposition, which he abstracted from the systems of material generated by his early compositions and improvisations. He wrote music for chamber ensembles and orchestra, vocal music, as well as for solo organ and piano, and also experimented with the use of novel electronic instruments developed in Europe during his lifetime.