Piano Concertos K. 107 (Mozart) Piano Concertos K. 107 (Mozart) The Piano Concertos, K. 107 are three keyboard concertos by Wolfgang Amadeus Mozart, based on sonatas by Johann Christian Bach. These sonatas are from J.C. Bach's Op. 5; Mozart turned Sonata No. 2 in D, Sonata No. 3 in G, and Sonata No. 4 in E from this set into the three concertos of K. 107. These concertos remained unpublished in the Alte Mozart-Ausgabe, the first complete edition of Mozart's works, so they were not given a number by the publishers of that edition, Breitkopf & Härtel (as the other 27 concerti were given in
Organ concertos, Op. 4 (Handel) of his oratorios Esther and Athalia. During this period Handel prepared the 16 movements of the four organ concertos HWV 290-293, of which 10 are reworkings of previous compositions with the remaining 6 largely newly composed. HWV 292, completed in March 1735, contains the most new material, although even there the ritornello of the first movement is a borrowing from Act 1 of Alcina. It featured in the April performances of Athalia at Covent Garden. The other concertos were first heard in March, HWV 290 and 291 in Esther and HWV 293 in Deborah. Handel completed Alexander's Feast in January