Piano concertos by Wolfgang Amadeus Mozart it was probably J.C. Bach, whom Mozart admired, who introduced the structural innovation of allowing the keyboard to introduce new thematic material in its first entry. Concertos Nos 1–4 (K. 37, 39, 40 and 41) are orchestral and keyboard arrangements of sonata movements by other composers. The next three concertos (K. 107/1, 2 and 3), which are not numbered, are arrangements of piano sonatas by J.C. Bach (Op 5. Nos. 2, 3, and 4, all composed by 1766). Based on handwriting analysis of the autographs they are believed to date from 1771–72. Concerto No. 5, K. 175 from 1773 was
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