Written in 1721, the Brandenburg Concerti are widely regarded as the greatest orchestral works of the Baroque period. They were dedicated to Christian Ludwig, the Margrave of Brandenburg. The second concerto is still known by trumpet players as one of the most difficult in the trumpet repertoire.
The piece is in the Italian concerto style of three movements (fast-slow-fast). It is voiced for two performing units, the concertino (natural trumpet, recorder, oboe, violin) and ripieno (accompanying strings and basso continuo). It is notable that the natural trumpet is left out of the second movement due to its inability to play in minor keys without the addition of valves.
The Brandenburg concertos are very consistent with all of the characteristics of the Baroque period. Most apparent is the concerto form, concerto grosso voicing, use of basso continuo, and virtuosic requirement of the soloists. In this case, hearing the piece truly speaks for itself in localizing it as Bach/Late Baroque.
Compared to other concerti grosso at the time, Bach differs in instrumentation by using different soloists for each of the six concerti. In general, though, the composition is a very standard example of Late Baroque music and the transition to Classical.
As a trumpet player and Beatles fan, I must admit that I chose this piece for its ties to the Beatles' "Penny Lane." The piccolo trumpet solo was written because the composer heard the second Brandenburg Concerto and thought the clarino natural trumpet sounded interesting. "Penny Lane" was also arranged and recorded by the Canadian Brass using a piccolo trumpet, in which the ending quotes Bach's second Brandenburg Concerto.
Bonds, Mark Evans. A History of Music in Western Culture. 4th ed. Upper Saddle River, NJ: Pearson Prentice-Hall, 2013.
Wolff, Christoph, et al. "Bach." Grove Music Online. Oxford Music Online. Oxford University Press, accessed March 23, 2014, http://www.oxfordmusiconline.com/subscriber/article/grove/music/40023pg10.