Keyboard concertos by Johann Sebastian Bach 1059) which adds an oboe to the strings and continuo. Most of Bach's harpsichord concertos (with the exception of the 5th "Brandenburg Concerto") are thought to be arrangements made from earlier concertos for melodic instruments probably written in Köthen. In many cases, only the harpsichord version has survived. They are among the first concertos for keyboard instrument ever written. The earliest extant sources regarding Bach's involvement with the keyboard concerto genre are his Weimar concerto transcriptions, BWV 592–596 and 972–987 (), and his fifth "Brandenburg Concerto", BWV 1050, the early version of which, BWV 1050a, may have originated before Bach
Brandenburg with Poland. Brandenburg originated in the Northern March in the 900s AD from areas conquered from the Wends, and later became the Margraviate of Brandenburg, a major principality of the Holy Roman Empire, with Albert the Bear as prince-elector. In the 17th century Brandenburg came under the rule of the House of Hohenzollern, the rulers of Prussia, who established Brandenburg-Prussia to become the core of the Kingdom of Prussia. Brandenburg became the Province of Brandenburg in 1815, a province within the kingdom and later within the Free State of Prussia. Brandenburg was established as a state in 1945 after World