created during this period to enhance the ceremonies at the cathedral. This musical
repertory developed in two phases. The first involved the compilation of the Magnus
liber organi by Léonin, named by the music theorist Anonymous 4 as the earliest
member of this school. This new polyphony, the most advanced music then devised,
introduced modal rhythm into segments of the polyphony known as discant clausulae,
which were composed in note-against-note style to the plainchant melismas, in contrast to
the lengthy and mellifluous lines improvised or composed to the syllabic sections of the
chant. The innovation of a musical notation for these clausulae proved a turning point in
western music. The clausulae grew in importance, as composers explored ways to
expand, extend, and notate increasingly complex rhythms; numerous independent
clausulae apparently intended to substitute for the original sections in the Magnus liber
organi survive in the Notre-Dame sources W1 and F. Some of these clausulae may have
been a factor in the abbreviatio (“abbreviation” or “revision”) of the Magnus liber organi
that Anonymous 4 attributed to Pérotin, whom he called optimus discantor.
The second phase consisted of revisions and additions introduced by Pérotin, whom
Anonymous 4 named as Léonin’s successor. It is probable that the notation if not much of
the music of the Magnus liber organi itself was revised and that new organum was added
over time, so that the three extant versions of the Magnus liber organi reflect three layers,
all of which apparently postdate the abbreviatio attributed to Pérotin. The version in the
Florence manuscript (F) may be closer to the liturgical practice of Notre-Dame and is
both larger and later than that in W1. Craig Wright has proposed, therefore, that the
version in F may be closer to Léonin’s Magnus liber organi and that dissemination from
Paris was selective rather than additive, as had previously been thought. Anonymous 4
also implied a distinction between the two phases that is valuable in understanding their
musical styles. Léonin’s polyphony is predominately two-part organum, whereas
Pérotin’s is generally discant in two, three, or four parts. This liturgical polyphony
quickly spread throughout Europe, notably in England and Spain, and manuscript
fragments in other northern regions indicate an even wider diffusion. As it spread,
however, the spirit of innovation that had imbued its formation was increasingly swept up
in the vernacular tide that began in the early 13th century, culminating in the French-
texted motet that dominated the second half of the century.
According to Anonymous 4, Pérotin also composed four- and three-part polyphony for
the Graduals and Alle-luias of Masses for Christmas, Easter, and the Nativity of the
Virgin Mary, and several conductus. The notational and rhythmic innovations of Pérotin
and ‘his colleagues in the cathedral were probably the basis of the earliest systematic
theoretical writings on the rhythmic modes, those attributed to Johannes de Garlandia,
which formed the “key” by which Friedrich Ludwig in the early decades of the 20th
century unlocked an understanding of the obscure notation of the Notre-Dame organa and
clausulae.
Sandra Pinegar
[See also: ANONYMOUS 4; CLAUSULA; LÉONIN; ORGANUM; PÉROTIN;
RHYTHMIC MODE]
Handschin, Jacques. “Was brachte die Notre-Dame Schule Neues.” Zeitschrift far
Musikwissenschaft 6 (1924):545–58.
Ludwig, Friedrich. Repertorium organorum recentioris et motetorum vetissimi stili. Halle am Salle:
Niemeyer, 1910.
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