Flute Sonata in E minor, BWV 1034
Johann Sebastian Bach
We have no real idea when or why Bach composed his E-minor Sonata, but it requires a player of the first order. The fast movements in particular are extremely demanding, not only because of the sheer rapidity of notes, many of them sharps or flats that have to be played with cross-fingerings or half-covered holes, but also because the player has to bring out important notes at the bottom of the flute’s range, where the instrument, like the recorder, is much quieter. Bach, unlike Vivaldi, was not much inclined to be merciful to musicians.
— Howard Posner