I. Allegro - The orchestra begins by playing the themes of the movement. The soloist enters and gives its own more decorated renditions of the themes. The orchestra repeats the themes before the flute develops them with added ornamentation and key changes. The main rhythmic theme is alternated with the soloist's statements as Bach keeps the momentum going to the end of the movement.
II. Un poco andante - A movement of smooth elegance that is not without sections of subdued drama for the soloist. Bach gives the soloist an opportunity for a cadenza shortly before the movement ends.
III. Allegro di molto - The movement begins in a whirl of rapidity that is maintained throughout. The music is a harbinger of the Sturm und Drang style of music that would come into fashion later in the 18th century. The opening theme returns throughout the movement and leads the soloist to run to keep up with the orchestra in music of great virtuosity and drama. The orchestra has the last word with a final statement of the main theme followed by an abrupt ending.
Bach took up the position of Cantor and Director of Music at Hamburg in 1768, and in his autobiography of 1777 he expressed his disappointment and frustration during his time in Berlin. Bach had gained the reputation of one of the great keyboard players in Europe early on, but it was his compositions that probably held him back from being more appreciated at court. As Annette Richards, organist, musicologist and authority on 17th and 18th century music has written:
Outside music, the cultural references of JS Bach were more or less exclusively theological. But with CPE Bach, things are completely different. Engaged with poets, painters, philosophers, his music is a reflection of the burgeoning secular discourse of his time. Even among his contemporaries you get a sense that CPE Bach is an acquired taste. His music – or the music he considered representative of his talents – is miles away from the elegance and balance we associate with this period. Timelines are crisscrossed, he is endlessly stopping and starting, wrong-footing the listener and causing his audience to reconsider its relation to the music. In that sense, it's very postmodern, a kind of meta-music.The composer himself had something to say about his style and originality in his autobiography:
Because I have had to compose most of my works for specific individuals and for the public, I have always been more restrained in them than in the few pieces that I have written merely for myself. At times I even have had to follow ridiculous instructions, although it could be that such not exactly pleasant conditions have led my talents to certain discoveries that I might not otherwise have come upon. Since I have never liked excessive uniformity in composition and taste, since I have heard such a quantity and variety of good [things], since I have always been of the opinion that one could derive some good, whatever it may be even if it is only a matter of minute details in a piece, probably from such [considerations] and my natural, God-given ability arises the variety that has been observed in my works…..Among all my works, especially for keyboard, there are only a few trios, solos, and concertos that I have composed in complete freedom and for my particular use.