Brandenburg Concerto No. 5 "Brandenburg Concertos" takes a central place. Nonetheless around half a dozen of Bach's extant concertos, including some of the "Brandenburg Concertos" and lost models of his later harpsichord concertos, seem to have had their roots in his Weimar period. Most of what Bach may have left with his employer in Weimar perished in a fire destroying Schloss Weimar in the 1770s. In 1719 a new large two-manual harpsichord arrived in the residence of Bach's then-time employer at Köthen. BWV 1050a, an extant early version of the fifth "Brandenburg Concerto", may have been conceived for this instrument, but that seems unlikely
Twelve Concertos, Op. 7 (Vivaldi) RV Anh. 142 (formerly RV 464); and No. 9 in B-flat major for violin, RV Anh. 153 (formerly RV 373). 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: