How did medieval motets create contrast among three voice parts?

In the medieval motet, composers created contrast among three voice parts primarily through the layering of distinct rhythmic and textual elements.12

Rhythmic Contrast

The contrapuntal style of the 13th century relied on the superimposition of different rhythmic modes—short, fixed rhythmic patterns—across the voices. While the lower voice, or tenor, held a slower-moving plainchant melody, the upper voices were distinguished by their own unique rhythmic patterns and phrase lengths. This created a hierarchy where the tenor served as a foundational "pillar," while the upper voices functioned as independent, soaring melodic lines.21

Textual Contrast

The motet was uniquely defined by the simultaneous presentation of multiple texts. Initially, a new text was added to the wordless upper voices of a descant clausula, while the tenor retained its original sacred Latin text. Over time, this evolved into a deliberate juxtaposition of languages and themes: the lower voice often maintained a sacred Latin text, while the upper voices featured secular texts in French. This layering allowed for a complex interplay between worldly and religious sentiments within a single composition.13