The greatest French organist of his day, Widor (1844–1937) composed 10 organ "symphonies" — actually solo compositions usually consisting of 6 or 7 short movements, that treat the organ as a kind of self-contained orchestra. Series I includes Symphonies Nos. 1–4, Op. 13 and Symphonie No. 5, Op. 42. Frequently performed today. Glossary of French terms.