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
Twelve Concertos, Op. 7 (Vivaldi) Twelve Concertos, Op. 7 (Vivaldi) A set of twelve concertos was published by Estienne Roger in 1716-1717 under Antonio Vivaldi's name, as his Opus 7. They were in two volumes, each containing concertos numbered 1-6. Of the set, ten were for violin solo; the other two were for oboe solo. The authenticity of some of the works included has long been doubted by scholars. Three are now considered spurious (i.e. not in fact by Vivaldi) for stylistic reasons. They are: No. 1 in B-flat major for oboe, RV Anh. 143 (formerly RV 465); No. 7 in B-flat major for oboe,