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
Province of Brandenburg the Bear, another Saxon count from the noble House of Ascania, who established the Margraviate of Brandenburg in 1157. His son Margrave Otto I already achieved the dignity of an Arch-Chamberlain of the Holy Roman Empire in 1177. Emperor Charles IV by the Golden Bull of 1356 confirmed the electoral dignity of the Brandenburg margraves and in 1373 assigned the electorate to his son Wenceslaus in 1373. The Elector of Brandenburg held the seventh rank among the electors of the Empire and had five votes in the Council of Princes. In 1415 Brandenburg was acquired by Burgrave Frederick of Nuremberg,