Brandenburg Concerto No. 5 "Brandenburg Concertos" takes a central place. Nonetheless around half a dozen of Bach's extant concertos, including some of the "Brandenburg Concertos" and lost models of his later harpsichord concertos, seem to have had their roots in his Weimar period. Most of what Bach may have left with his employer in Weimar perished in a fire destroying Schloss Weimar in the 1770s. In 1719 a new large two-manual harpsichord arrived in the residence of Bach's then-time employer at Köthen. BWV 1050a, an extant early version of the fifth "Brandenburg Concerto", may have been conceived for this instrument, but that seems unlikely
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,