theme and variations
A form where a musical theme is stated then altered in successive variations.
In Depth
Theme and variations is a form where a musical theme is stated clearly, then repeated in a series of altered versions. Each variation preserves something essential — usually the harmonic structure or the melody — while changing other elements like rhythm, tempo, key, texture, or ornamentation. The form allows a composer to explore a single idea from many angles, demonstrating both imagination and technical skill. Mozart's Ah, vous dirai-je, Maman variations (on the tune known as Twinkle, Twinkle, Little Star) is a charming example. Beethoven's Diabelli Variations and Bach's Goldberg Variations represent the form's highest achievements — entire worlds built from a single theme.
Beethoven's Diabelli Variations started as a joke — the publisher sent Beethoven a simple waltz theme and asked for a single variation. Beethoven wrote 33, creating one of the greatest piano works ever composed.