Léonin, also known as Leoninus, Leonius, or Leo, was the first important composer of polyphonic organum, a type of music with multiple voices singing together. He was likely French and probably lived and worked in Paris at the Notre-Dame Cathedral. He was the first known member of the Notre-Dame school of polyphony and the ars antiqua style to have his name recorded, thanks to a writer known as Anonymous IV. While no other details are certain, the name "Leoninus" and its Latin form "Leo" are similar to the French names Léonin and Léo.
Overview
Our knowledge about Léonin comes from a 13th-century student at a cathedral, known as Anonymous IV. This English student wrote a treatise about music theory and mentioned Léonin as the composer of the Magnus Liber, a collection of organum called the "great book."
The Magnus Liber, as it was reconstructed from later manuscripts, contains many clausulae. These are parts of Gregorian chant with many notes sung on one syllable. These sections were separated from the original chant, which was played very slowly. A faster upper melody was added on top of these slower parts. Léonin may have been the first composer to use rhythmic modes and might have created a way to write them down. According to W.G. Waite, who wrote in 1954, "Léonin’s greatest achievement was to introduce a clear system of rhythm into polyphonic music for the first time. He also created a way to write down this rhythm."
The Magnus Liber was meant to be used in religious services. Anonymous IV wrote that "Magister Leoninus (Léonin) was the finest composer of organum. He wrote the Magnus Liber for the gradual and antiphoner used in sacred services." All the music in the Magnus Liber is for two voices, but little is known about how it was actually performed. The two voices were not necessarily sung by soloists.
See also Medieval music.
Musicologist Craig M. Wright believes Léonin may have been the same person as a Parisian poet named Leonius, after whom Leonine verse may have been named. This could make Léonin’s use of meter even more important. Another possible name is Henricus Leonellus, who lived at the Abbey of St. Victor from about 1163 to 1192.