Johann Sebastian Bach’s third Brandenburg Concerto plays a rich game of uniformity and multiplicity, expanding exponentially upon the tradition of the concerto grosso. There are three groups of three instruments in this third concerto, and each instrument must bounce periodically from being ripieno to concertato. It is in effect a concerto grosso for nine instruments, each of whom spends time playing tutti for his own orchestra.
The work is based around a very simple three-note germ, which instantly takes on a Jack-and-the-Beanstalk life of its own, growing immediately from seed to something much larger (and full of seeds itself).
There is some argument about the second movement, which is all of two notes long. Since there is a fermata on the second note, it is necessary to assume that there might have been some ornamentation or improvisation (especially for the keyboard, which is the only instrument not to have had its concertato moment). Some play a movement from one of the violin sonatas, some just play the chords. At the time of this writing, we have not yet decided what to do in this concert…
The Brandenburg concertos were dedicated in 1721 to the Margrave Christian Ludwig of Brandenburg. It seems, however, that they were written separately some time before, collected, and then presented to the Margrave for some Royal reason (a ‘command’ is mentioned). The third concerto was likely the first one of the set to be put to paper.