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 and the lands of the Hevelli from their last Wendish ruler, Pribislav, in 1150. After crushing a force of Sprevane who occupied the town of Brandenburg in the 1150s, Albert proclaimed himself ruler of the new Margraviate of Brandenburg. Albert, and his descendants the Ascanians, then made considerable progress in conquering, colonizing, Christianizing, and cultivating lands as far east as the Oder. Within this region, Slavic and German residents intermarried. During the 13th century, the Ascanians began acquiring territory east of the Oder, later known as the Neumark (see also Altmark). In 1320, the Brandenburg Ascanian line came to an