G-flat major Rondo-Finale of his Seventh Symphony. Mahler's Tenth Symphony was composed in the enharmonic key of F-sharp major. This key is more often found in piano music, as the use of all five black keys allows an easier conformity to the player's hands, despite the numerous flats. Austrian composer Franz Schubert chose this key for his third impromptu from his first collection of impromptus (1827). Polish composer Frédéric Chopin wrote two études in the key of G-flat major: Étude Op. 10, No. 5 "Black Key" and Étude Op. 25, No. 9 "Butterfly". French composer Claude Debussy used this key for one
Serenade in E-flat major (Saint-Saëns) structured as a single movement marked "Allegretto tranquillo, quasi andantino". Performance time is around 6 to 7 minutes. Serenade in E-flat major (Saint-Saëns) Camille Saint-Saëns' Serenade in E flat major, Op. 15 () is a chamber composition for a quartet consisting of piano, organ, violin, viola (or cello) composed in 1865. It is one of the earliest works by the composer making use of an organ (or harmonium) in a chamber ensemble, preceded only by the Six Duos for harmonium and piano, Op. 8. In addition to the original scoring the work has been transcribed for orchestra, piano solo, piano