What is 'Cento partite sopra passacagli' best described as?

• A. A sacred motet set
• B. Variations on a ground bass
• C. An opera in multiple acts
• D. A collection of vocal madrigals

Answer: (B)

The main idea is that this work is built on a repeating bass pattern and uses variations over it. Cento partite sopra passacagli is a set of one hundred variations on a ground bass, specifically a passacaglia, composed for the organ. The bass line stays constant while the upper voices, textures, rhythms, and ornamentation continually change, showcasing the performer’s technique and creativity within a fixed framework. This contrasts with a sacred motet (a vocal sacred piece with text), an opera (a staged drama with acts and singers), or a collection of vocal madrigals (secular polyphonic songs for voices); none of those describe an instrumental variation set over a repeating bass.