The so-called Vatican Organum Treatise (henceforth VT), or ‘Ars organi’, included in the composite manuscript Ottoboni lat. 3025 in the Biblioteca Apostolica Vaticana is believed to have been copied in northern France (or possibly England) around the middle of the thirteenth century.The most comprehensive work on the treatise is F. Zaminer, Der vatikanische Organum-Traktat
(Ottob. lat. 3025): Organum-Praxis der frühen Notre Dame-Schule und ihrer Vorstufen
(Münchner Veröffentlichungen der Musikwissenschaft, 2; Tutzing, 1959). Recent con-tributions
include I. Godt and B. Rivera, ‘The Vatican Organum Treatise—A Colour
Reproduction, Transcription, and Translation’, in In Memoriam Gordon Athol Anderson
(Institute of Mediaeval Music, Musicological Studies, 39/2; Binningen, 1984), pp. 264 1
ff., and L. Treitler, ‘Der vatikanische Organumtraktat und das Organum von Notre
Dame de Paris: Perspektiven der Entwicklung einer schriftlichen Musikkultur in
Europa’, Basler Jahrbuch für historische Musikpraxis, 7 (1983), 23-31. Bernhard Bischoff, the
palaeographer whom Zaminer consulted (p. 24), has dated the treatise c. 1225-50, plus
or minus twenty years. The filigree script of VT (about 60% of the size of the scripts of
F, W 2 or W 1 ) closely compares with the following dated manuscripts published in C.
Samaran and R. Marichal, Catalogue des manuscrits en écriture latine portant des indications de
date, de lieu ou de copiste, 6 vols. (Paris, 1959-68): Paris, Bibliothèque Nationale de France
[hereafter BN] lat. 8097 (Tours, 1232), Paris, BN lat. 15652 (Paris, 1240-5), Paris, BN
lat. 15143 (1270), Paris, BN lat. 15133 (1270) and Charleville, Bibliothèque municipale
25 (before 1281). The treatise transmits a theoretical tract as well as a large repertory of musical examples, including three organum settings. The tract of VT, along with thirty-one rules regarding simple two-voice progressions, is related to certain discant treatises that stand in the ‘old’ Ad organum faciendum tradition of the early twelfth century, treatises whose dissemination throughout Europe reaches well into the fourteenth and fifteenth centuries;See Zaminer, Der vatikanische Organum-Traktat, pp. 42-71; S. Fuller, ‘Theoretical Foundations of Early Organum Theory’, Acta musicologica, 53 (1981), pp. 52 ff.; ead., ‘Early Polyphony’, in The New Oxford History of Music, ii: The Early Middle Ages to 1300, ed. R. Crocker and D. Hiley (Oxford and New York, 1990), pp. 508-28; K.-J. Sachs, ‘Zur
Tradition der Klangschritt-Lehre: Die Texte mit der Formel “Si cantus ascendit . . .” und ihre Verwandten’, Archiv für Musikwissenschaft, 28 (1971), pp. 233 ff.; and H. H. Eggebrecht and F. Zaminer, Ad Organum faciendum: Lehrschriften der Mehrstimmigkeit in nachguidonischer Zeit (Mainz, 1970). The closest relatives of VT are the ‘Louvain’ (edition: CS II, pp. 494a-496b), ‘Pseudo Guido’ (CS II, pp. 191b-192b), ‘Si cantus equalis’ (CSM IV, pp. 38-40 and Sachs, ‘Zur Tradition’, pp. 244-5) and ‘Venice’ treatises (Zaminer, p. 134). For the most recent contribution on this subject consult Michael Bernhard's forthcoming article ‘Eine neue Quelle für den Vatikanischen Organum-Traktat’
(Quellen und Studien zur Musiktheorie des Mittelalters, 3; Bayerische Akademie der Wissenschaften, Veröffentlichungen der Musikhistorischen Kommission). The relevant text is found in G. P. A. Bolton Library (formerly Cathedral library), Tipperary, Cashel MS 1 – a composite source of medieval treatises – and corresponds to the rule section of VT beginning ‘De regulis organi’. As the Cashel text does not include the first two sections (or 42 lines) of VT – ‘Incipit ars organi’ and ‘Vis in organo’ – and has no musical examples, it stands squarely in the tradition of the simple voice-leading manuals. Most scholars of voice-leading treatises are well aware of the ‘anom-alous’ character of VT (cf. Fuller, ‘Early Polyphony’, p. 527). the numerous musical examples and three organum settings (with a duplum voice in a florid style), however, are related to the ‘new’ organum coming out of Paris.
