There are seven complete concertos for a single harpsichord (BWV 1052–1058), three concertos for two harpsichords (BWV 1060–1062), two concertos for three harpsichords (BWV 1063 and 1064), and one concerto for four harpsichords (BWV 1065).
From 1729 to 1741, Bach was director of the Collegium musicum in Leipzig, a student musical society, founded by Georg Philipp Telemann in 1703.
The Collegium musicum often gave performances at Zimmermann’s coffee house. It was for these occasions that Bach produced his harpsichord concertos, among the first concertos for keyboard instrument ever written.
It is thought that the multiple harpsichord concertos were heard earlier than those for one harpsichord, perhaps because his sons C. P. E. Bach and W. F. Bach (both excellent harpsichord players) were living at home until 1733 and 1734.