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
Manuscript choirbook (Capp. Sist. 160, 1510's) in mensural notation, showing the opening of Missa Virgo Parens Christi by J. Barbireau
B. Cordier, "Belle bonne sage"
The Kyrie of Ockeghem's Missa prolationum in the Chigi codex (Chig. C. VIII 234, music09, NB.03)
In medieval music, the rhythmic modes were set patterns of long and short durations. The value of each note is not determined by the form of the written note, but rather by its position within a group
Mensural notation
…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…
Pérotin, "Alleluia nativitas", in the third rhythmic mode.
Pérotin, Viderunt omnes (Gradual for Christmas Day), in the first rhythmic mode. MS Florence, Biblioteca Medicea-Laurenziana, Pluteo 29.1, fol. 1 recto.