In medieval polyphony, the cantus firmus is usually placed in which voice?

• A. Soprano
• B. Alto
• C. Tenor
• D. Bass

Answer: (C)

The cantus firmus acts as a fixed melodic anchor for the piece, giving the other voices a stable reference point to move around. In medieval polyphony, this chant-like line is placed in the tenor because the tenor typically carries longer, slower note values, allowing the upper voices (and any lower voices) to weave intricate counterpoint above it while still aligning to consonant intervals on important beats. This arrangement keeps the texture balanced: the cantus firmus remains relatively steady, providing clarity and structure, while the other voices explore melodic and rhythmic elaboration. Putting the cantus firmus in the soprano or bass would disrupt that balance—either making the texture too busy at the top or too heavy at the bottom—whereas the tenor offers the ideal ground for the chant to endure as the central, unifying line.