Keyboard concertos by Johann Sebastian Bach soloists, were all adapted into harpsichord concertos by the composer, BWV 1058, 1054 and 1062 respectively. It is often assumed that Bach's extant violin concertos were written in his Köthen period (1717–1723): it can however not be proven from documentary evidence that any of them existed prior to around 1730. In September 1725 Bach performed organ music, accompanied by other instruments, in Dresden. The works he performed there have not been identified. More than a year later he composed several cantatas with an organ obligato part. Several movements of such cantatas were derived from earlier lost concertos, and resurfaced in
Keyboard concertos by Johann Sebastian Bach timing matched the publication of the first ever collection of keyboard concertos, the widely acclaimed and well-selling Organ concertos, Op.4 of George Frederic Handel published in London and Paris in 1738. The harpsichord concertos were composed in a manner completely idiomatic to the keyboard (this was equally true for those written for two or more harpsichords). They were almost certainly originally conceived for a small chamber group, with one instrument per desk, even if performed on one of the newly developed fortepianos, which only gradually acquired the potential for producing a louder dynamic. The keyboard writing also conforms to a