Bach of J.S. Bach’s immortal creations has its own particular story. Scrutiny of the composer’s surviving manuscripts not only provides us with a better understanding of his well-known classical masterpieces, but also gives us the opportunity to restore those compositions whose artistic conception was never realised by Bach himself… Only nine incomplete bars remain of the last composition in the large Leipzig manuscript from the late 1730s, the autograph of Bach’s solo keyboard concertos (BWV 1052–1059). This material coincides with the music in the introductory passage (the “Sinfonia”) for the first movement of the sacred cantata BWV 35 (“Spirit and Soul Become Confused”, 1726). Apparently Bach’s approach to the composition of keyboard concerto BWV 1059 was simply to adapt an earlier piece for orchestra, and this (like many other instrumental pieces in Bach’s Leipzig cantatas) may in turn have been a “paraphrase” of a movement in quick tempo from one of the composer’s lost instrumental concertos written during the Cöthen period.