Léonin

Léonin is one of the very first European composers whose name we know, yet his life remains partly mysterious. Scholars usually identify him with Leonius, a poet and canon active in Paris in the second half of the twelfth century, born around 1135 and dead around 1201. He is thought to have been educated at the Paris cathedral school, one of the great intellectual centres of the age, before joining the clergy of Notre-Dame.

His name has come down to us thanks to an English theorist of the late thirteenth century whom musicologists call “Anonymous IV”. Writing about a century later, this witness describes him as “optimus organista”, the best composer of organum, and credits him with a great collection of polyphonic chants for the whole liturgical year: the Magnus liber organi, the “great book of organum”. He adds that the book was later revised and shortened by his successor, Pérotin.

Organum means adding one or more voices above a Gregorian chant. In Léonin’s music the liturgical melody is stretched into very long notes in the lower voice, while the upper voice unfolds long, supple, ornate vocalises above it: this is organum duplum, in two voices. In certain passages, called clausulae, the two voices instead move together in a tighter, more rhythmic way. This alternation gave the cathedral’s great feasts a new solemnity.

These innovations developed at the very moment Notre-Dame de Paris was being built, its construction beginning in 1163. Léonin’s music shares that impulse: like Gothic architecture, it reaches for height and breadth. It also relies on a decisive advance in notation, the rhythmic modes, which allowed long and short durations to be shown through groups of notes. It was one of the first steps towards the measured rhythm of Western music.

The Magnus liber organi has not survived in its original form: we know it through manuscripts copied in the thirteenth century, now kept in Florence, Wolfenbüttel and Madrid, which mix older pieces with later revisions. It is therefore impossible to attribute each organum to Léonin with certainty. Among the pieces tradition links to him are the Christmas Viderunt omnes and the Easter Alleluia Pascha nostrum.

To understand what people heard then, we must imagine the great resonant nave and a small group of soloists in the middle of the choir. Only the sections given to the soloists, in responsories and alleluias, were sung in polyphony; the rest of the chant remained Gregorian, in unison, taken up by the whole clergy. Léonin’s organum thus slotted into the liturgy as a festive moment, a burst of sound reserved for the most solemn days of the year: Christmas, Easter, Pentecost, the Assumption. The collection covers a complete cycle of some ninety pieces. Singers had to know the underlying Gregorian melody by heart and improvise part of the ornamentation: the boundary between written composition and oral practice was still blurred, and it is precisely Léonin’s work that began to fix on parchment what had previously been improvised.

Léonin is regarded as the first representative of what is called the Notre-Dame school, which made Paris the capital of European polyphony for more than a century. His organa, carried as far as Spain and Scotland, served as models for generations of singers. Without him, the history of music in several voices would probably not have taken the same path.