Passacaglia
Variation form over a constantly repeated bass theme, usually in triple time.
What it means
The passacaglia is a variation form over a constantly repeated bass theme, usually in slow triple time and in the minor. Over the unchanging bass the upper voices change in a series of variations that often build towards a climax. The name goes back to the Spanish pasacalle ("to walk through the street"), a dance that guitarists played between songs.
Musical use
In the 17th century the passacaglia became an instrumental form in Italy and Germany, for instance with Frescobaldi and Buxtehude. Johann Sebastian Bach's Passacaglia in C minor for organ (BWV 582), with its twenty variations, is a high point. Later Brahms in the finale of his Fourth Symphony and Anton Webern in his Passacaglia, Op. 1 (1908) used the form.
The passacaglia should be distinguished from the chaconne, which rests on a repeated chord progression; the two forms are often mixed and hardly strictly separated. The ostinato is the more general term for any repeated figure.
Performance practice
When you play a passacaglia, always listen to the bass theme: it is the backbone of the piece. Build the climax patiently across the variations and articulate the sections clearly.