This article is about a style of music. For the musical instrument, see organum (musical instrument).

Organum (stress is on first syllable: OR-ga-num) is a technique of singing developed in the Middle Ages and is an early form of polyphonic music. In its earliest stages, organum involved two musical voices: a melody, and the same melody transposed by a consonant interval, usually a perfect fifth or fourth. In these cases usually the composition began and ended on a unison, maintaining the transposition only between the start and finish. Organum was originally improvised; while one singer performed a notated melody (the "vox principalis"), another singer—singing "by ear"—provided the unnotated second melody (the "vox organum"). Over time, composers began to write added parts that were not just simple transpositions, and thus true polyphony was born.

The first document to describe organum specifically, and give rules for its performance, was the Musica enchiriadis (c. 895), a treatise traditionally (and probably incorrectly) attributed to Hucbald of St. Amand . In its original conception, organum was never intended as polyphony in the modern sense; it was intended as a reinforcement of the sound of unison singers. It is also made clear in the Musica enchiriadis that octave doubling was acceptable, since it was inevitable when men and boys sang together; and it was also acceptable to double parts with instruments.

Organum as a musical genre reached its peak in the twelfth century with the development of two very different schools of organum composition: the St. Martial School of florid organum, which may have been centered around the monastery of St. Martial in Limoges, and the Notre Dame school of organum of Paris (see: rhythmic mode), which included composers such as Leonin and Pérotin, and out of which grew most of the later forms such as the motet.

See also

• Medieval music
• Gregorian chant
• Musica enchiriadis
• Johannes Cotto
• St. Martial School
• Notre Dame School

References and further reading

• Various articles, including "Organum," "Musica enchiriadis", "Hucbald", "St Martial" in The New Grove Dictionary of Music and Musicians, ed. Stanley Sadie. 20 vol. London, Macmillan Publishers Ltd., 1980. ISBN 1561591742
• Richard H. Hoppin, Medieval Music. New York, W.W. Norton & Co., 1978. ISBN 0393090906