Brandenburg Concerto No. 4 BWV 1049

Library of Congress

One of Johann Sebastian Bach’s greatest qualities was his mental agility. He could execute complicated feats of concentration and invention — improvising intricate fugues on command, or writing the same tune against itself at two different speeds. Not only did his music make sense, it was meltingly lovely at the same time.

He was also enviably unfettered when it came to imagining instrumental colors and combinations. Take the line-up for this piece: a solo group of violin and two recorders (or flutes) and an accompanying string band of two violins, viola, violone, cello and continuo. Not hugely promising. Yet, in his hands, they sound at once robust and feather light. For long stretches, the solo violin is the lowest instrument playing — a high bass line if there ever was one! Its sound world gives this concerto a delightful freshness that is outstanding, even among the glories of the Bach’s output as a whole.

All the Brandenburg Concertos date from around 1720 — we do not have exact dates, but it seems certain they were not written for the Margrave of Brandenburg. His name ends up on them almost by accident.

Bach’s days as a Kapellmeister to the music-loving prince of Anhalt-Cöthen were coming to an end in the early 1720s, so he started looking for a new job. The wealthy Margrave of Brandenburg seemed a promising prospect, and he sent him a beautifully produced set of six concertos — the Brandenburg Concertos. What should have happened is that the margrave, overwhelmed by the gift, should have offered Bach the job of a lifetime. However, Bach seems to have misjudged things. The margrave never responded at all; instead, he packed Bach’s lavish gift away in his library.

In any case, the margrave’s loss is our good fortune — and Bach’s, too. It seems that the margrave’s band was mediocre, a pale shadow of Bach’s ensemble at Anhalt-Cöthen, for whom the concerto was almost certainly written. In time, Bach secured a far better job with far better musicians. His magnificent gift was preserved safe and sound in the margrave’s library, and it is now the only surviving source for the six marvelous concertos that stand head and shoulders above pretty well any similar works of the period.