The Earliest Polyphonic Music

Origins and Development.

The most far-reaching addition to music during the Middle Ages was the invention of polyphony—music in more than one part—an aspect of Western art that is not duplicated in any other culture. The idea itself undoubtedly originated centuries earlier than the earliest written evidence or even the first mention in theoretical treatises. In its simplest forms polyphony can easily be improvised as, for example, when two or more performers simultaneously sing the same song at different pitches, and it still exists in that form in a number of cultures. But the musicians of Europe took the idea quite a bit further, developing and refining the practice to a level of complexity that could not be extemporized, but required long thought-out and calculated written composition. Monophonic music, both chant and the secular compositions, continued to be performed throughout the Middle Ages and long after, but once invented, polyphony invaded all forms with dramatic consequences. It added an entire new body of works to sacred music, supplementing the chant and even replacing it on special occasions. The effect was somewhat different on secular music, where polyphonic music became the treasured repertory of the upper classes, creating a musical class distinction that had not existed previously.

The Earliest Forms.

Instruction and information about polyphony is found in theoretical treatises from as early as the De harmonica institutione (Melodic Instruction), written by the monk Hucbald c. 900, and later expanded and developed in a number of treatises including Micrologus (Little Discussion), by Guido of Arezzo. The basis of the technique comes from parallel motion, which is described by Hucbald as the sound that results when a man and a boy sing the same melody simultaneously, each one in his own range. Extensions of this idea include refinements made by one of the voices varying from exact parallel at different times, creating different harmonies, or one voice moving slowly while the other moves quickly, filling in the gap with ornamental passages. All of these techniques are known as "organum," and the earliest written examples of the technique can be found in eleventh- and twelfth-century manuscripts from England and France. By the twelfth century additional experiments revolving around the monastery of Saint-Martial in Limoges (central France) involved composing two lines of music with separate melodic profiles, which resulted in constantly changing harmonies between the two parts. It is at this point that we can mark the true beginning of composed polyphony, the most distinguishing mark of Western art music.

Notre Dame Organum and the Substitute Clausulae.

Along with the construction of the Gothic Cathedral of Notre-Dame in Paris in the twelfth century came distinctive and far-reaching experiments in composition of a new polyphonic repertory by two of the cathedral's choirmasters: Master Leonin and Master Perotin. These compositions, called organum, consisted of a new added part above the traditional chant. Leonin (c. 1135–1201) is credited with originating the Magnus liber organi (Great Book of Organum), which contains several different kinds of innovative compositions, including organum sections for Graduals, Alleluias, and Responsories for the entire liturgical year. Leonin's organum compositions were intended to be substitutes for those phrases of plainchant usually sung by a soloist. When organum passages are applied to a chant, the result is an interruption of the monophonic performance with a section in which a rapid upper part is sung by a soloist against the long, sustained lower notes of the original chant, followed by a return to the unison chanting of the choir. The new sections are known as substitute clausulae because their purpose was to take the place of a phrase (clausula) already present in the chant.

Discant.

Perotin, who followed Leonin as leader of the Notre-Dame cathedral choir, took the next step and added to the substitute repertory in the form of a new rhythmic organization of the original chant notes with a much lower ratio between the number of notes in the upper and lower parts. Perotin's style of composition, called discant, brings a heightened sense of rhythmic flow to the substitute sections. In performance, therefore, an Alleluia in which both organum and discant sections have been substituted would take on a format in which, for example, only three sections of plainchant performed by the whole choir might be alternated with six sections of organum or discant. The change from the original plainchant version of the Alleluia would be that the choir participation has been substantially reduced because both organum and discant sections are performed by two soloists, one of whom sings the original chant while the other adds the newly composed organum or discant melody above it.

sources

Reinhard Strohm and Bonnie J. Blackburn, eds., Music as Concept and Practice in the Late Middle Ages. The New Oxford History of Music 3.1 (Oxford: Oxford University Press, 2001).