Charles Tournemire

Charles Arnould Tournemire was a French composer and organist, notable partly for his improvisations, which were often rooted in the music of Gregorian chant. His compositions include eight symphonies, four operas, twelve chamber works and eighteen piano solos. He is mainly remembered for his organ music, the best known being a set of pieces called L’Orgue mystique.

Adapted from the Wikipedia article on Charles Tournemire.