Organ concertos, Op. 4 (Handel) had already been established during his one-year position as cathedral organist in Halle in 1702. Handel's organ concertos thus have a special place in his oeuvre. They paved the way for Mozart and Beethoven, who like Handel achieved fame in their lifetimes as composers and performers of their own concertos. In the sinfonias of some of his cantatas, Johann Sebastian Bach had already introduced concerto movements for organ and orchestra. However, Bach's organs in both Weimar and Leipzig were large organs with double keyboards and pedals, powerful instruments that could only dominate a baroque orchestra. Bach's organ writing in the
Brandenburg the Province of Brandenburg, again subdivided into the government regions of Frankfurt and Potsdam. In 1881, the City of Berlin was separated from the Province of Brandenburg. However, industrial towns ringing Berlin lay within Brandenburg, and the growth of the region's industrial economy brought an increase in the population of the province. The Province of Brandenburg had an area of and a population of 2.6 million (1925). After World War II, the Neumark, the part of Brandenburg east of the Oder–Neisse line, was transferred to Poland; and its native German population expelled. The remainder of the province became a state