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
RBB Brandenburg RBB Brandenburg RBB Brandenburg (until May 2003 ORB-Fernsehen) was the "third television channel" for Brandenburg, Germany from January 1992 to March 2004. Until May 2003, it was organized by Ostdeutscher Rundfunk Brandenburg (ORB), then by its successor, Rundfunk Berlin-Brandenburg (RBB). On 1 March 2004, the two regional television channels of RBB - "RBB Brandenburg" and "RBB Berlin" - were integrated into the new rbb Fernsehen. The programme was launched on 1 January 1992 under the name "Fernsehen Brandenburg". In the initial build-up phase, the then ARD cultural television programme Eins Plus was taken over from 3 p.m. to 5.15 p.m.