Keyboard concertos by Johann Sebastian Bach left Weimar in 1717. Many of Bach's orchestral harpsichord concertos are adapted from a model with one or more violin solo parts. Several of these earlier models are extant. The oldest of these is Vivaldi's concerto for four violins, RV 580, published in 1711, model for Bach's concerto for four harpsichords, BWV 1065. Bach replaced the part of his fourth "Brandenburg Concerto", BWV 1049, composed in 1721 or earlier, by a harpsichord part when he reworked it to the harpsichord concerto BWV 1057. Bach's extant violin concertos BWV 1041–1043, two for a single violin soloist and one for two violin
Organ concertos, Op. 4 (Handel) In November and December 1734, Handel presented various opera revivals and a newly composed opera-ballet "Terpsichore". However the combination of dance and opera seria was not sufficient to attract the opera going public. In January 1735 Ariodante opened, but, despite the quality of the music and a visible royal presence, was no more successful. It was in March that Handel started his first oratorio season, featuring the organ concertos HWV 290-293. The timing of the performances avoided conflicts with events in other London theatres and the local papers advertised the "new Concertos on the Organ." In spite of this his