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 Brandenburg Brandenburg (; , Lower Sorbian: "Bramborska", ) is a state of Germany. Brandenburg is located in the northeast of Germany covering an area of and has a population of 2.5 million residents, the fifth-largest German state by area and tenth-most populous. Potsdam is the state capital and largest city, while other major cities include Brandenburg an der Havel, Cottbus, and Frankfurt (Oder). Brandenburg surrounds the national capital and city-state of Berlin, which together form the Berlin/Brandenburg Metropolitan Region, the third-largest metropolitan area in Germany. Brandenburg borders the states of Mecklenburg-Vorpommern, Lower Saxony, Saxony-Anhalt, and Saxony, and an international border