Mark Zier
[See also: BERENGAR OF TOURS; GREGORIAN REFORM; GREGORY VII;
NORMANS IN SICILY]
Gilchrist, John T., trans. Collection in Seventy-four Titles: A Canon Law Manual of the Gregorian
Reform. Toronto: Pontifical Institute of Mediaeval Studies, 1980.
——. Diversorum patrum sententiae: sive, Collectio in LXXIV titulos digesta. Vatican City:
Biblioteca Apostolica Vaticaʼna, 1973.
Garreau, Albert. Saint Léon IX, pape alsacien, réformateur de l’église, 1002–1054. Paris: Tolra,
1965.
Krause, Hans Georg. Das Papstwahldekret von 1059 und seine Rolle im Investiturstreit. Rome:
Abbazia di San Paolo, 1960.
Petrucci, Enzo. Ecclesiologica e politica di Leone IX. Rome: ELIA, 1977.
Sittler, Lucien, and P.Stintzi, eds. S. Léon IX, le pape alsacien. Colmar: Alsatia, 1950.
LÉONIN
(Leoninus; fl. 1154-ca. 1201). Anonymous 4’s epithet optimus organista (“the best
singer/improviser/ composer/compiler/notator of organum”) assured Léonin a significant
place in music history long before any convincing identification of the person was
suggested. Since he was responsible for the new polyphonic repertory of the cathedral of
Notre-Dame in Paris in the decades after its founding in the 1160s, his place was
evidently among the dignitaries of its ecclesiastical hierarchy, but the familiar use of the
Latin diminutive of his name, as “Magister Leoninus,” in the theoretical treatise of
Anonymous 4—the only source for information on his considerable musical
achievement—long seemed to belie this. Anonymous 4 credited Léonin with the Magnus
liber organi de gradali et antifonario some one hundred years after its compilation, a fact
that recommends cautious use of his testimony and the need for independent verification.
Three major manuscript sources (W1, F, and W2) confirm a repertory of organum that fits
Anonymous 4’s description of a Magnus liber organi, and the melodies of the plainchant
that form the basis of that organum match notated plainchant sources used at Notre-
Dame. Still, this does not clarify what Léonin’s role may have been in making such a
book. Optimus organista suggests a youthful man in full voice, while the diminutive
implies a beloved elder whose practical contributions may have been overshadowed by
his administrative usefulness—two very different “portraits” of the individual. It may not
have been so much by his initiative as by his approval that modal rhythm became the
primary innovation of the Notre-Dame School, and there is no certain evidence that such
rhythm was subject to systematic theoretical or notational principles during his lifetime.
Archival evidence only recently brought to light establishes a probable identity for
Anonymous 4’s Magister Leoninus as Magister Leoninus presbyter, a canon active in the
affairs of the cathedral during the late 12th century and a Latin poet whose hexametric
Old Testament commentary, Hystorie sacre gestas ab origine mundi, was long praised
after his death. There is, however, no document, except possibly the treatise of
Anonymous 4, to substantiate the involvement of Leoninus presbyter with music at all, a
striking omission given the significance of the Magnus liber organi and the stature of the
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