Théodore Dubois (1837-1924) was choirmaster at Madeleine and took over from Cesar Franck as choirmaster at Stainte-Clotilde. 1877 he returned to the Madeleine as successor of Saint-Saëns.
He dedicated the "Dix Pièces" to his friend Georges Jacob. When Dubois composed this pieces he had an two-manual organ in mind, as he stated in a footnote - so St. Eucaire was the first choice!