Widor, Charles Marie (shärl märēˈ vēdōrˈ) [key], 1845–1937, French organist and composer. He was organist at St. Sulpice from 1869 until his retirement in 1934. In 1891 he succeeded César Franck as professor of organ at the Paris Conservatory and later also became professor of composition there. Chief among his compositions are 10 symphonies for organ. He composed operas, chamber music, orchestral suites, and piano concertos as well. In 1904 he wrote a supplement to Berlioz's treatise on orchestration. He also made, with Albert Schweitzer, an edition of the organ works of Bach.