the Ars Antiqua) in Book 7 of his Speculum musicae of 1325. Finally, a letter of Pope
John XXII (1324–25) proscribes the application of certain musical techniques, some of
which are recognizably characteristic of the Ars Nova, to church music.
The “new art” (more properly “new technique”) originally concerned the notation of
rhythm. Building upon the foundation of Franco of Cologne’s notational theory (ca.
1280), Jehan des Murs—the role of Philippe de Vitry is unclear—took Franco’s
principles of imperfection (in triple meter, subtracting a third part of a note) and
alteration (in triple meter, doubling the value of a note to fill two beats of a three-beat
unit) and systematically applied them to both longer and shorter note values, thereby
vastly increasing the repertory of rhythmic durations available to the composer. A new
note shape, the minim, was introduced for the short values. The full admission of duple
(“imperfect”) divisions alongside the old triple (“perfect”) divisions is a principal
characteristic of Ars Nova notational theory, and the system provides for the notation of
works in our modern time signatures of 9/8, 6/8, 3/4, and 2/4. Finally, by means of notes
written in red instead of black ink, provision was made for changing between perfect and
imperfect time within a work, although composers did not fully exploit ramifications of
this innovation until the late 14th-century Ars Subtilior.
The first practical source of Ars Nova music is a beautifully illuminated manuscript of
the Livres de Fauvel (B.N. fr. 146; ca. 1318). Alongside musical insertions of Ars
Antiqua motets and conductus are isorhythmic motets of the early Ars Nova. Although no
works are attributed in the manuscript, some are probably by Philippe de Vitry. The
isorhythmic motet provided the perfect expression for Ars Nova notational developments,
exploiting a wide range of durational values in rigorously logical musical works laid out
hierarchically with very slow note values in the tenor and fast note values in the motetus
and triplum.
Besides the isorhythmic motet genre, the Ars Nova also contributed innovations in the
chanson genres. The manuscript of the Roman de Fauvel contains a fascicle of chansons
in dance forms by Jehannot de Lescurel (d. 1304?). These works, including one three-
voice and thirty-one monophonic chansons, are noticeably more florid and rhythmically
varied than comparable works of the 13th century (e.g., the rondeaux of Adam de la
Halle). Jehannot’s cultivation of dance lyrics set to advanced rhythms announced a shift
of emphasis in the secular song. All that remained after further consolidation of the
poetry of the dance lyrics as the fixed forms—ballade, rondeau, and virelai—was the
musical addition of an untexted accompanying voice, a step probably taken ca. 1340 by
Guillaume de Machaut.
Around 1350, with the mature polyphonic fixed-form chansons of such composers as
Machaut and Pierre des Molins, the mature isorhythmic motets of Philippe de Vitry,
Machaut, and others, and the authoritative summa of the notational system found in the
Libellus cantus mensurabilis of Jehan des Murs, the Ars Nova entered its high phase. In
the course of the 1370s, 1380s, and 1390s, developments in the notation of extremely
complex rhythms preoccupied composers particularly in the south, at the courts of Gaston
Phoebus at Béarn, the popes at Avignon, and John I of Aragon. This phase is now most
often called the Ars Subtilior.
Lawrence Earp
The Encyclopedia 135