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
Piano concertos by Wolfgang Amadeus Mozart orchestra" rather than the more obviously "piano" concertos of the nineteenth century (e.g., that of Grieg etc.). Because Mozart was developing the form of his concertos as he wrote them and not following any preconceived "rules" (apart, presumably, from his own judgement of taste), many of the concertos contravene one or other of the generalisations given above. For example, K. 488 in A major lacks new expositional material, and "merely" repeats the preludial material; further, it effectively merges the first ritornello and the middle section, as does K. 449 in E. Several of the later concertos do not hesitate to