Bach compiled the C minor concerto for two harpsichords in Leipzig in the 1730s, when he was directing the Collegium Musicum and needed material for weekly performances at Zimmermann's coffee house. The two solo parts are treated as equals rather than as soloist and accompanist, and the slow movement is a duet over pizzicato strings in which neither instrument leads. The concerto is almost certainly an arrangement of a lost work for two melody instruments, and it is now often played in that reconstructed form as well, for oboe and violin.