Organum

A voice added above a sustained chant, and Western polyphony begins.

Related

MedievalCounterpointVoice

Organum adds one or more voices to chant, turning a single melody into polyphony. It is the earliest Western polyphony that could be written down.

Origins

A ninth-century treatise, Musica enchiriadis, records the first method: a parallel voice below the chant, mostly at the fourth, fifth or octave. In the twelfth century singers at Saint-Martial and Notre Dame made the upper voice florid, setting a sustained tenor against fast figuration. Léonin compiled the Magnus liber; Pérotin expanded the texture to three and four voices, and mensural notation let the parts align exactly.

Listening features

The lowest voice stretches each chant note into a long tenor, while the upper voice runs above it. Vertical intervals are mainly fourths, fifths and octaves; thirds and sixths are not yet the base of consonance. Early organum has no fixed beat; later repeating rhythmic patterns slice time into cells. Hold on to the long note and hear the figuration circle back to it.

Composers and works

Léonin and Pérotin represent the Notre Dame school. Pérotin's Viderunt omnes and Sederunt principes build four-voice organum on a grand scale. The anonymous Winchester organum preserves an earlier parallel style.

Lineage

After chant, organum branches into conductus and clausula; the clausula gained words and became the motet, and its polyphony led toward the Renaissance Mass.

Misconceptions

Organum is not unison singing, nor Bach-style functional harmony. It does not use only thirds and sixths: fourths and fifths were the consonances of the day. Pérotin did not invent organum; he built on Léonin and an older tradition.

Sources

• The New Grove Dictionary of Music and Musicians, 2nd ed., entry "Organum" — terms and dating checked, not quoted
• Richard Hoppin, Medieval Music (Norton, 1978) — repertory checked, not quoted

Used for fact-checking only; all prose is original.