ARS ANTIQUA. — This is the name given, in contrast to the Ars nova (v.) of the 14th century, to the sacred composition of the first period of polyphony (9th–13th centuries), usually summarized in the theory of the Franconian school and in the technical genres « organum » or « diaphonia » and later « discantus », including other forms such as: « rondellus », « conductus », « copula », « motetus » and « hoquetus ». This period, in which music, drawing extensively upon the purest sources of the liturgy, is enriched by a vast sacred repertory in which the vital sap of Gregorian chant reigns supreme, may be divided into three phases, each lasting approximately a century: the 1st, opened by Hucbald of St-Amand, the distinguished Benedictine theorist of the 9th century, is closed by the Micrologus (1030) Guido d'Arezzo (v.); the 2nd is closed by the Magnus Liber organi of Leonino, and the 3rd culminates in the reforming and PETRONIO (v.). Of the two kinds of sources, monuments of practical music and theoretical treatises, the latter, in the first phase, are the sole aid for the study of primitive polyphony; in the 19 chapters of the Musica Euchriadis, Hucbald suggests various types of diaphony with harmonic intervals (« symphoniae ») of 4ths, 5ths and 8ths between the « vox principalis » (a chant taken from the Gregorian repertory) and the « vox organalis » (an added chant), while Guido, in chaps. 18 and 19 of the Micrologus, proposes major 2nds, major and minor 3rds, and especially 4ths, rejecting minor 2nds and 5ths. The 2nd phase provides us with important treatises, such as the anonymous Ad organum faciendum of Milano (Ambr. Library, MS M 17 Supl., ca. 1100), the 12 rules of Quicunque venit dechanter (11th–12th century; Paris, National Library, f. lat. 15139, formerly St-Victor 813), the Discantus positio vulgaris (attributed to Roberto da Sabillon or J. de Garlandia), from the 12th century, the Epistola ad Fulgentium of J. Cotto (also 12th century), as well as precious monuments of practical music: we may mention, for example, three « organum » pieces for 2 voices, including the trope on the kyrie Cunctipotens Genitor Deus and the alleluia Iustus ut palma from the aforementioned manuscript of the Ambrosiana, the 5 alleluias for 2 voices added in the 11th century to a Musica Euchriadis of the 9th–10th centuries (Chartres, Municipal Library, 130 [148]), and the Winchester Troper (Cambridge, Corpus Christi College 473), to which must be added the « organa » of St. Martial of Limoges contained in 4 MSS now in Paris (National Library, f. lat. 1139, 3549 and 3719) and London (Br. Mus., add. 36681). The primitive 2-voice « organum » in parallel motion, which had gradually been transformed into discant through the predominance of contrary motion, is now enriched with additional voices: from the three-voice discant (triplum), with intervals of 5ths and 8ths proposed by Francone of Cologne, forms are reached in which superimposed upon the tenor (Gregorian chant) are a « duplum », also called « medius cantus » or « motetus » (from which the form takes its name), a « triplum » (« tertius cantus » or « discantus »), and often also a « quadruplum » and a « quintuplum ». The 3rd phase adds to discant, besides contrary motion, that mensuralism which, already foreshadowed by the modal rhythm inspired by the metrical patterns of verse, is now devel-
oped by the theorists of the Franconian school (Petrus de Cruce, J. de Garlandia, Francone of Paris and Francone of Cologne, 13th century) and expressed graphically by the new notation, with signs corresponding to the different duration values of sounds. In practical music we have reached the culminating point of the whole a. a., namely the flowering of the school of the cathedral of Paris which, with Leonino (mid-12th century), had established itself at the center of the musical world of its time.
The oldest manuscript of the Parisian choir is represented by cod. Wolfenbüttel Helmst. 628, but the richest collection is found in the Antiphonarium Mediceum (Florence, Mediceo-Laur. Library, Plut. XXIX, 1), a true jewel of art. Other manuscripts contain motets with texts no longer in Latin but in French, an indication of that process of secularization and of that movement away from the pure Gregorian tradition which would reach its culmination in the Italian (especially Tuscan) and French Ars nova (v.) of the 14th century.