Concerto for Three Violins in D major, BWV 1064R

BWV 1064 survives as a concerto for three harpsichords in C major, made in Leipzig in the 1730s for the Collegium Musicum that met at Zimmermann's coffee house, where Bach could count on his sons and pupils to fill the solo parts. The writing points to an earlier concerto for three violins, now lost; editors reconstruct that version a tone higher, in D major, because the violin figuration lies naturally there. Both forms are performed today, and the difference of key is the clearest sign of which one is meant.