The Golberg Variations BWV 988 by J. S. Bach, is an excellent example of variations in the baroque period. It is a work of great proportions based on a theme titled Aria followed by 30 variations.
The Aria is in binary form. Each part is made of two phrases:
Here is the structure of the Aria:
All variations follow this structure (we will discuss minor variations later). Most sections have 16 measures, but in some variations, two measures are combined into one, so each section has only eight measures. In variation 16 (overture), part B has 32 measures. In this case, two 3/8 measures of part B correspond to one measure in the Aria.
Some harmonic variations of the original are found. Here we compare the Aria and the first variation with variations marked in red:
|Key||G major||D major|
|Aria (theme)||I||V||vi - vii / V||V||I - V / IV||ii||V||I||I - vii / re||I||ii||V||I - V / IV||IV - ii||V||I|
|Variation 1||I||V||vi - V / V||V||I||ii||V||I||I||iii||ii||V||I||IV - ii||V||I|
Measures 17 to 32:
|Key||G major||E minor||G major|
|Aria (theme)||V||I||VI - ii||V||i||VI||ii - V||i||ii||I||ii||V||I - V / IV||IV||V||I|
|Variation 1||V||I||iv - ii||V||i||iv||V - vii/V - V||i||ii||I||ii||V||I - V / IV||IV - V - vii/ii - ii||V - I - V||I|
The G and D minor keys are used instead of the major keys. In part B, instead of E minor, Bach modulates to E flat major:
Variation 15 is a canon at the fifth using mirror inversion (the sixteenth notes motive is imitated in the second measure one fifth above and the interval direction is inverted). The two upper voices make the canon over the bass: