|Johann Christian Bach 1735 - 1782|
Johann Christian Bach, often called the "London Bach" because of his residence there, was the youngest son of Johann Sebastian Bach and, measured by success in his life, a more important composer than his father. One indication is the above portrait, painted by the very famous English painter, Thomas Gainsborough. J. C. Bach was an eminent composer in one of the great capitals of Europe, while his father was merely a somewhat obscure Saxon organist. The very young Mozart on tour with his father, was pleased to be able to spend time with the great master in London. So it seems to be the case that we tend to underrate the importance of J. C. Bach, overshadowed as he is by those three composers that overlapped and came immediately after him: Haydn, Mozart and Beethoven. Looking on Amazon, there seems to be only one artist devoting much time to J. C. Bach, this is the conductor Anthony Halstead who has done recordings of the complete symphonies, symphonies concertantes and keyboard concertos.
It turns out that J. C. Bach was, in addition to being pretty important in his own right, also a big influence on Mozart. How big? Mozart's first three piano concertos were arrangements of keyboard sonatas by J. C. Bach. Here is the first movement of Mozart's K. 107, arranged from a keyboard sonata in D by J. C. Bach.
When I say "arranged" I don't mean "transcribed". In other words, Mozart did not transfer the notes over to a small ensemble of violin 1, violin 2 and cello without "fixing" the form. The problem, as Charles Rosen relates in his book Sonata Forms, pp. 71 et seq., is that the J. C. Bach original has a sonata exposition and what is needed in the concerto is a ritornello. The mid-18th century was a confusing transition in compositional design, but the basic problem with the opening section for orchestra is that in sonata expositions, there is a modulation to the dominant, but in a concerto ritornello it was preferred to keep this section in the tonic so as to avoid taking away from the dramatic entry of the soloist. As you can hear in the opening exposition, while there is a cadence ON the dominant, the music immediately returns to the tonic and cadences in the tonic before the entry of the keyboard.
In the J. C. Bach original, however, the sonata exposition ends with several emphatic cadences in A major, the dominant:
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For comparison, here is the end of the Mozart arrangement, the end of the opening ritornello, just before the entry of the soloist:
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Solid cadence in D major and Mozart ends the opening phrase of the solo with a half cadence on V of V:
These concertos were published in 1777 when J. C. Bach was at the peak of his maturity. Mozart would have been twenty-one at the time and therefore open to influence. The basic form of the first movement at this time is this (where R stands for orchestral ritornello and S for solo, in this case keyboard solo):
R S R S R S R
I I--V V --vi I I I
The Roman numerals below the sections indicate the harmony as it was largely through harmony that the form was articulated. Sometimes, as in the case of this concerto, the third solo and third ritornello are combined. As is nearly mandatory, the movement ends with the opening theme, forte. The second movement is a lyrical andante with pizzicato strings. The last movement is in the form of variations on a Scottish folksong. Here is the beginning of the first movement:
Listening you will hear the opening ritornelli cadencing in Bb at the end. The first solo modulates to F, the dominant. Eighteenth century music always modulates to the dominant. As far as the form is concerned, the question is when, exactly.
I'm a bit surprised at how good J. C. Bach's keyboard concertos are. We tend to think that the world of the concerto was shrouded in darkness until Mozart came along. But that's not true, is it? The keyboard concertos of J. C. Bach at least are quite good pieces that were probably an inspiration to Mozart.