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
Hansa-Brandenburg B.I Hansa-Brandenburg B.I The Hansa-Brandenburg B.I was an unarmed military trainer and reconnaissance biplane of World War I, flown by the Austro-Hungarian Air Service. Early models were known internally to the Hansa-Brandenburg firm as the type D, while later models with a more powerful engine were designated FD. This aircraft was one of the earliest designs of Ernst Heinkel, who was working for Hansa-Brandenburg at the time. It was an entirely conventional two-bay biplane with staggered wings of unequal span. The pilot and observer sat in tandem in a long open cockpit. The aircraft was produced under license by Aero, both