Keyboard concertos by Johann Sebastian Bach soloists, were all adapted into harpsichord concertos by the composer, BWV 1058, 1054 and 1062 respectively. It is often assumed that Bach's extant violin concertos were written in his Köthen period (1717–1723): it can however not be proven from documentary evidence that any of them existed prior to around 1730. In September 1725 Bach performed organ music, accompanied by other instruments, in Dresden. The works he performed there have not been identified. More than a year later he composed several cantatas with an organ obligato part. Several movements of such cantatas were derived from earlier lost concertos, and resurfaced in
Ketzel, the Cat who Composed Ketzel, the Cat who Composed Ketzel, the Cat who Composed is a children's picture book by Lesléa Newman. Based on a true story, it is about the friendship between Moshe Cotel and a kitten, Ketzel, who composes a musical piece that Cotel enters into a music competition and receives a special mention. "BookList" gave "Ketzel" a star review, wrote "this delightfully told story is unlikely and adorable in equal parts. Bates' watercolor, gouache, and pencil illustrations feature an unanthropomorphic kitty whose inquisitive and quizzical nature will be familiar to all cat owners." and found it "An absolute charmer!" and the