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-Prussia the Catholic-Imperial camp in the Treaty of Königsberg (1627) and accept garrisons. When the Swedish Empire entered the war and advanced into Brandenburg, George William again claimed neutrality, yet Gustavus Adolphus of Sweden compelled George William to join Sweden as an ally by occupying substantial territory in Brandenburg-Prussia and concentrating an army before the town walls of Berlin. George William did not conclude an alliance, but granted Sweden transit rights, two fortresses and subsidies. Consequently, Roman Catholic armies repeatedly ravaged Brandenburg and other Hohenzollern lands. During the Thirty Years' War, George William was succeeded by Frederick William, born 1620, who