mensuralnotation

Mensural notation is a European musical notation system developed in the late Middle Ages for notating rhythm in polyphonic music. It evolved from earlier Franconian notation and the Ars Nova, introducing measured rhythm through specific note shapes and ligatures that indicated relative durations rather than mere pitch. The principal note values include longa, breve, semibreve, and the shorter values semiminima and minim, with their exact lengths determined by the surrounding mensural signs.

Rhythm in mensural notation is governed by tempus (time) and prolation (subdivision). A sign for tempus indicates whether the beat is divided in a perfect (triple) or imperfect (duple) manner, while prolation shows how those values are subdivided into two or three parts. Notes could be grouped in ligatures, which conveyed rhythmic patterns that could span multiple notes and beats. Coloration, typically seen as red notes, could alter the proportion of a note group, enabling complex patterns such as diminution and rhythmic modulation.

The system reached its peak in the 14th and 15th centuries during the Ars Nova period and in the works of the Burgundian School. It allowed greater rhythmic variety and precise control in polyphony than earlier chant-based notation, supporting more intricate technique and structure in masses, motets, and secular songs. Mensural notation gradually gave way to modern staff notation in the 16th and 17th centuries, though its concepts influenced early printed music theory and practice.

Today, mensural notation is central to the study of medieval and early Renaissance music, offering essential insight into how rhythm was conceived and notated before the modern metric system.