This is the third movement of the Suite in A major by J. S. Bach, which is my transcription of the First Cello Suite in G major, BWV 1007. Here is the first movement and here is the second.
There are only two basic forms used in the Baroque suite: the prelude and the binary dance form, though occasionally one runs into a rondeau such as the Gavotte en rondeau from the E major violin partita. The two basic forms could be compared to prose and poetry in literature. The prelude is a very free kind of form without repeated sections. It tends to be one large gesture. Sometimes it is just a series of arpeggiated chords, other times it can resemble an Italian concerto movement. But the form of the prelude always contrasts with the dance movements that follow in its openness and free structure. It is like prose, it just flows.
The rest of the suite is nearly always a series of dances, the four 'core' dances, the allemande, courante, sarabande and gigue with galanteries or optional dances often inserted between the sarabande and the gigue. All these dances have the same form: AABB, that is, they are in two halves, the second usually a bit longer, and each half repeats. Performers often leave out the repeat of the second half, but in my recording, I repeat both halves. Harmonically, the first half usually moves to a cadence on the dominant (in a minor key, often on the relative major). So in this suite, in A major, the first half of every dance movement has a cadence on E major. In the second half, the music returns to the tonic and ends with a cadence on A major. Every movement does exactly the same thing! But how the music goes to the dominant and returns to the tonic is different every time! And Bach and every other Baroque composer did this in hundreds and hundreds of dance movements. Bach just did it better.
The clip today is of the third movement, the courante. This courante is in the Italian style, quick and without the hemiolas one finds in the French-style courantes. To accompany the performance I have included a portrait of Bach as a young man (disputed by some), an etching of the Thomaskirche in Leipzig where Bach spent most of his career as cantor, the beginning of my edition of the courante and some photos of me.