The middle movement is a reworking and transposition of material from the slow movement of the sonata for organ in D minor, BWV 527; both movements are thought to be based on a prior lost composition. Like the slow movement of the fifth Brandenburg Concerto, the slow movement of BWV 1044 is scored as a chamber work for the solo instruments. In binary form, the harpsichord alternates in repeats between upper and lower keyboard parts of BWV 527/2; the other melodic keyboard part is played alternately by flute or violin, while the other instrument adds a fragmentary accompaniment in semiquavers (scored as pizzicato for the violin).