J. S. Bach, (1685-1750) a prominent organist in his time, was an extremely prolific composer of many works - cantatas, solo instrumental sonatas, works for keyboard, and concerti such as the Brandenburg concerti. This arrangement is based on the 3rd Movement of his Italian Concerto, published in 1735. Here it is arranged for violin and viola. Suitable for intermediate and advanced students, amateurs, and professionals.
This piece can also be viewed in its entirety here (noteflight.com allows a user to play along to a score - useful especially for students).