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 with Poland. Brandenburg originated in the Northern March in the 900s AD from areas conquered from the Wends, and later became the Margraviate of Brandenburg, a major principality of the Holy Roman Empire, with Albert the Bear as prince-elector. In the 17th century Brandenburg came under the rule of the House of Hohenzollern, the rulers of Prussia, who established Brandenburg-Prussia to become the core of the Kingdom of Prussia. Brandenburg became the Province of Brandenburg in 1815, a province within the kingdom and later within the Free State of Prussia. Brandenburg was established as a state in 1945 after World