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) Organ concertos, Op. 4 (Handel) The Handel organ concertos Op 4, HWV 289–294, are six organ concertos for chamber organ and orchestra composed by George Frideric Handel in London between 1735 and 1736 and published in 1738 by the printing company of John Walsh. Written as interludes in performances of oratorios in Covent Garden, they were the first works of their kind for this combination of instruments and served as a model for later composers. Handel's six organ concertos were published in 1738 by John Walsh as the composer's Opus 4. The four concertos HWV 290-293 had been written to