We discuss Bach's chamber work Brandenburg Concerto No. 1
According to Wikipedia:
Bach's reference to his scoring the concertos for "several instruments" (Concerts avec plusieurs instruments) is an understatement. Bach used the "widest spectrum of orchestral instruments … in daring combinations," as Christoph Wolff has commented. "Every one of the six concertos set a precedent in scoring, and everyone was to remain without parallel." Heinrich Besseler has noted that the overall forces required (leaving aside the first concerto, which was rewritten for a special occasion) tallies exactly with the 17 players Bach had at his disposal in Köthen.