On 24 March 1721 Johann Sebastian Bach sent Christian Ludwig, Margrave of Brandenburg, the scores of six concerti “for various instruments.” The Margrave, whom Bach had met in 1719 in Berlin, was a passionate music lover who collected the scores of more than two hundred concerti by various composers in addition to being a strong proponent of Antonio Vivaldi. Bach’s Brandenburg concerti were based on a model created by Vivaldi (almost all are in three movements and feature wind instruments), but each of them is highly original. No two are alike, each is unique, and together they comprise a veritable encyclopaedia of Baroque music.

Concerti Nos 3 and 6, unlike the other four, are concerti grossi (Baroque concerti for several soloists and orchestra). They were composed for chamber ensembles in which one person would perform each part, thus making each performer a soloist. When performed by a greater number of musicians one becomes a concerto grosso, the other an orchestral concerto.

Concerto No 3 was intended for three violins, three violas, three cellos and basso continuo. The symbol of the Trinity insistently comes to mind, which the basso continuo seems to disturb. But Bach composed this part, too, on three different lines for three different instruments – the cello, violone and harpsichord. He later transformed the first movement of the concerto into the introduction to Cantata No 174, Ich liebe den Hцchsten von ganzem Gemьte (I Love the Highest with My Whole Heart, 1729). Instead of a second movement, there are just two fluctuating chords written in the score. Possibly this meant an improvised cadenza from the violin, harpsichord or other instrument; by putting something akin to a series of dots in the score, Bach was quite literally inviting the performers to work with him.

Brandenburg Concerto No 6 was composed for two violas, two violas da gamba and basso continuo. In a break with tradition, the “Cinderella” violas perform the solo, the noble violas da gamba accompanying. This can probably be explained by the fact that Bach’s then patron, the Prince von Anhalt-Kцthen, loved to play the da gamba while Bach himself liked to play the viola (it is not hard to imagine which of the two was the more virtuoso performer!). In the second movement the da gambas fall silent and, to the background of an accompaniment continuo, the violas carry the infinitely beautiful two-voiced fugue. If the number of performers is increased, Concerto No 6 becomes a concerto grosso for two violas and low strings.
Anna Bulycheva