As with most of his instrumental music, we know little about the origin of the three Bach works on this program. They probably date from after 1730, when Bach was not only the Cantor of Leipzig’s St. Thomas Church, in charge of liturgical music in three Lutheran churches, but also director of the Leipzig Collegium Musicum, which played Friday night concerts in Zimmerman’s Coffee House in an era before there was such a thing as a concert hall.

The orchestral suite, or ouverture, was one of the most popular instrumental forms in Germany: although Bach wrote only four of them, other composers turned them out by the dozens.  A French import, the suite consists of a series of dance movements preceded by a French overture: a stately, often pompous, opening and a closing section with a faster, usually fugal, second section.  The overture was the biggest and most important of movements, which is why a suite was often called an ouverture.

Few French overtures are as important or imposing as the one that starts Bach’s Third Suite, a blazing fanfare of a beginning leading to a dense and energetic fugue. The Air that follows is a complete change, with the winds dropping out and the principal violin spinning out an exquisite long-lined melody. The Gavotte, Bourrée, and Gigue that follow are dance types that were familiar to Bach’s audience.

Just as Germans imported the suite from France, they imported the concerto from Italy, and Bach himself was heavily involved in the transalpine trade: the 11 arrangements of Vivaldi concertos he made are testimony to his fascination with the Italian master. His Concerto for Two Violins shows Vivaldi’s influence in the brisk rhythms and outgoing character of the outer movements, and much of the solo writing.

But the counterpoint is unmistakably Bach. All three of the concerto’s movements are fugues, a structural choice that springs naturally from having one soloist constantly repeating what the other does. This sort of canonic follow-the-leader might become tiresome in other hands, but Bach created outer movements of great energy and vigor, and a middle movement of sublime beauty.

The Sinfonia in D survives in a bound manuscript, the cover of which describes it as “Intrada or Concerto,” indicating it is an introduction to something. The heading on the score itself calls it a “Concerto, a 4 Voci.  3 Trombe, Tamburi, 2 Hautb, Violino Con[certato], 2 Violini, Viola e Cont[inuo],” the reference to four voices meaning that it is the first movement of a vocal work.  Squeezed between those words and the first staff of the score is the word “Sinfonia.”  So we have a few choices about what to call it, but it is likely an introductory movement from an unidentified or lost church cantata, one of a number of Bach cantata opening movements dominated by a solo instrument. The manuscript breaks off in the middle of the 150th measure. It has a brief conclusion in the hand of someone other than Bach; most performers use a more developed conclusion that goes back to the opening.

— Howard Posner