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
Brandenburg-Prussia after the victory at Fehrbellin and the Brandenburg-Prussian advance in Swedish Pomerania during the Scanian War, Frederick William decided to establish a navy. He engaged Dutch merchant and shipowner Benjamin Raule as his advisor, who after a first personal meeting with Frederick William in 1675 settled in Brandenburg in 1676 and became the major figure of Brandenburg-Prussia's emerging naval and colonial enterprise. The Brandenburg-Prussian navy was established from ten ships which Frederick William leased from Raule, and achieved first successes in the war against Sweden supporting the siege of Stralsund and Stettin and the invasion of Rügen. In Pillau (now