Mensural notation

Mensural notation is the musical notation system used for polyphonic European vocal music from the late 13th century until the early 17th century. The term "mensural" refers to the notation of precise rhythmic durations based on numerical proportions of note values. Its modern name is derived from the terminology of medieval theorists, who used terms like musica mensurata ("measured music") or cantus mensurabilis ("measurable song") to refer to the rhythmically defined polyphonic music of their age, as opposed to musica plana or musica choralis, i.e., Gregorian plainchant. Mensural notation was employed principally for polyphonic vocal music, while plainchant retained the older system of neume notation throughout the period, and some instrumental music was written in various forms of instrument-specific tablature notation. Mensural notation grew out of an earlier, more limited method of notating rhythms in terms of fixed repetitive patterns, called rhythmic modes, which were developed in France around 1200. An early form of mensural notation was described and codified in the treatise Ars cantus mensurabilis ("The art of measured chant") by Franco of Cologne (c. 1280). An expanded system allowing for greater rhythmic complexity was introduced in France with the stylistic movement of the Ars nova in the 14th century, while Italian 14th-century music developed its own, somewhat different variant. Around 1400, the French system was adopted across Europe and became the standard form of notation for 15th- and 16th-century Renaissance music. Over the course of the 17th century, mensural notation gradually evolved into modern measure (or bar) notation. The salient innovation of mensural notation was the systematic use of different note shapes for rhythmic durations, used in well-defined, hierarchical numerical relations to each other. This made note lengths less context-dependent than in the earlier rhythmic mode notation, but a note's length could be equal to either two or...