ARS NOVA. — This was the name given to the current of renewal in sacred composition that animated polyphonic music from the early years of the 14th century to the beginning of the 15th and that, while on the one hand it benefited the progress of notation (v.) through the introduction of binary time in place of ternary time and the creation of small values—minim, semiminim, quaver, and semiquaver—originating in the instrumental practice of dance pieces and in the technical virtuosity of vocal pieces, on the other marked the beginning of that secularization of church music which, expressed in the ever deeper detachment from Gregorian chant, later culminated in the rich fifteenth-century Flemish contrapuntal architecture built upon popular themes, checked only two centuries later by the Council of Trent, with its hoped-for return to Gregorian chant as the direct performance or inspiration of polyphony.
Of the two great groups of sources—theoretical treatises and monuments of practical music—the first is notably scarce in comparison with the second, especially when one considers the vast abundance of treatises from the preceding period, that is, ars antiqua (v.). The first decisive step toward the a. n. is found in the writings of Marchetto da Padova, who, after the Lucidarium in arte musicae planae (1274), wrote, around 1309, the Pomerium artis musicae mensurabilis, in which, among other things, he illustrates the new Italian notation. Shortly thereafter, around 1325, we find the celebrated treatise by Philippe de Vitry entitled A. n.; the expression, also used in the writings of his friend Joannes de Muris, Ars novae musicae, gave its name to the entire movement. Apart from several other small treatises, still unpublished, by certain masters of musical practice (among them Jacopo, Paolo, and Zaccharias), we may finally mention Marchetto’s great fellow citizen, Prodocimo de Beldemandia, who, in his Tractatus practicae de musica mensurabili ad modum Italicorum, written about a century later (around 1410), offers a retrospective view of the notation of fourteenth-century Italy anticipated by Marchetto. The two Paduan theorists may therefore be considered, broadly speaking, as the boundary points between which the musical world of the Italian a. n. moved and operated.
From the practical point of view, sacred music in this period reflects the absence of the great liturgical cycles that in the ars antiqua accompanied the course of the ecclesiastical year; and the only five or six parts of the Ordinarium Missae that are now set to music themselves appear to have been composed under the direct influence of the five forms then in vogue: the motet, the French « ballade », the « conductus », the madrigal, and the caccia. We thus have three important cycles of the « Ordinarium »: the Mass of Tournai, for three voices, still very close to the thirteenth century in its modal rhythm and notation; the Mass of G. Machaut, for four voices, among the oldest examples of the genre, both composed in the style of the « conductus »; and finally a collection by authors from northern and central Italy (Paris, ital. 568) which, together with another smaller collection of Romagnol origin (Vat. Urb. 1419), provides us with several significant examples of fourteenth-century Italian art. Of the religious production of the French a. n. there remain two famous manuscripts originating in Avignon (first half of the 14th century), now in Ivrea and Apt, containing motets and Masses in the manner of the secular motet, the « conductus », and the French ballad, as well as, among other pieces (in Ivrea), a Credo in that isorhythmic form which the great musician-poet Machaut favored in order to realize, in his motets, the postulates of Ph. de Vitry. The ecclesiastical music of this period, although present and abundant in the various countries for accompanying the ceremonies of worship, was nevertheless so permeated by the secular elements invading the field of music that Pope John XXII (1324–25) was compelled to raise his voice against the abuses that removed sacred chant from its true function of liturgical homage and invitation to prayer.