Analysis of the third movement
Bach’s use of structure and tonality
First, we can look at the way in which the final movement of this concerto is organised, by using a simple tabular approach that shows the main thematic material and key centres.
The overall structure of the movement is fairly simple ternary form or ABA, arranged as follows:
Section A Bars 1-78 Begins in D major (tonic) and moves to A major
Section B Bars 79-232 Begins and ends in B minor (relative minor) with some
sections in F# minor and A major. Includes a reminder of the A section material.
Section A Bars 233-310 A repeat of the opening A section.
The themes are presented in fugal style, meaning that there are always several melodic lines weaving together and imitating each other, creating a polyphonic, contrapuntal texture. In a fugue, the main melodic idea is called the subject, and is usually followed by the same idea in another part, beginning on a different note and called the answer. The first part will normally continue to develop the subject while the answer is being played (called a countersubject) and other parts may come in with subjects or answers. This particular movement has many entries of the subject and answer, creating complex polyphony.
The piece is essentially monothematic in that it has one main theme, and all other themes are derived from it. Very often there are two thematic ideas at the same time.
Most of the melodic material is conjunct but the subject begins with a leap of a fourth.
There are many sequences.
As would be expected in Baroque music, there are ornaments – mainly trills in the harpsichord part.
There are a number of appoggiaturas in the B section.