Bach’s six concertos dedicated to the Margrave of Brandenburg were completed in 1721. They are supreme examples of the concerto grosso form, though in some of them the solo instrument takes the spotlight to turn the work into a fully developed concerto. The Fourth is a concerto for violin with two recorders.
In the large-scale Fifth concerto, Bach produced in effect a full-blown keyboard concerto, with a huge first movement cadenza of 65 bars. Given the complexity of the solo part, it is likely that Bach himself played the harpsichord at the performances for the Prince in Berlin where he had purchased a magnificent new instrument. The Sixth concerto reverts to the concerto grosso form, but with unusual scoring -there are no violins. This gives the work a dark, warm tone with the violas dominating the wonderful slow movement.