In the middle of Handel’s Messiah is a piece called “Pifa,” played only by the orchestra. The “Pifa,” which takes its name from the pifferi, or shepherds’ flutes, was used as a title not only by Handel but also by other contemporary composers. It was a kind of convention. Corelli, a composer of the Baroque era, also included a “Pifa” in his concerto grosso. It is quite interesting to compare it to Handel’s.