Ars nova was a stylistic period in music of the Late Middle Ages, centered in France, which encompassed the period roughly from the preparation of the Roman de Fauvel (1310 and 1314) until the death of Machaut (1377). Sometimes the term is used more generally and refers to all European polyphonic music of the 14th century, thereby including such figures as Francesco Landini, who was working in Italy. Occasionally the term "Italian ars nova" is used to denote the music of Landini and his compatriots (see Music of the Trecento for the concurrent musical movement in Italy). The term ars nova means "new art" or "new technique", and was first used in a publication of the same name by Philippe de Vitry (c. 1322).
Ars nova is generally used in conjunction with another term, ars antiqua, which refers to the music of the immediately preceding age, usually extending back to take in the period of Notre Dame polyphony (therefore covering the period from about 1170 to 1320). Roughly, then, the ars antiqua is the music of the thirteenth century, and the ars nova the music of the fourteenth; many music histories use the terms in this more general sense.
Controversial in the Roman Catholic Church, the music was starkly rejected by Pope John XXII, but embraced by Pope Clement VI. The monophonic chant, already harmonized with simple organum, was becoming altered, fragmented, and hidden beneath secular tunes. The lyrics of love poems might be sung above sacred texts, or the sacred text might be placed within a familiar secular melody. It was not merely polyphony that offended the medieval ears, but the notion of secular music merging with the sacred and making its way into the liturgy.
Stylistically, the music of the ars nova differed from the preceding era in several ways. Developments in notation allowed notes to be written with greater independence of rhythm, shunning the straitjacket of the rhythmic modes, which prevailed in the thirteenth century; secular music acquired much of the polyphonic sophistication previously found only in sacred music; and new techniques and forms, such as isorhythm and the isorhythmic motet, became prevalent. The overall aesthetic effect of these changes was to create music of greater expressiveness and variety than had been the case in the thirteenth century. Indeed the sudden historical change which occurred, with its startling new degree of musical expressiveness, can be likened to the introduction of perspective in painting, and it is useful to consider that the changes to the musical art in the period of the ars nova were contemporary with the great early Renaissance revolutions in painting and literature.
The greatest practitioner of the new musical style was undoubtedly Guillaume de Machaut, who also had an equally distinguished career as a priest and poet. The ars nova style is nowhere more perfectly displayed than in his considerable body of motets, lais, virelais, rondeaux, and ballades.
Towards the end of the fourteenth century a new stylistic school of composers and poets centered on Avignon in southern France developed; the highly mannered style of this period is often called the ars subtilior, though some scholars choose to consider it a late development of the ars nova rather than breaking it out as a separate school. This strange but interesting repertory of music, limited in geographical distribution (southern France, Aragon and later Cyprus), and clearly intended for performance by specialists for an audience of connoisseurs, is like an endnote to the entire Middle Ages.