The Beginning of Modern Music — Leonin and Perotin

Notre Dame Cathedral in Paris France
Notre Dame Cathedral in Paris France | Source

Leonin, Perotin, and the School of Music at Notre Dame

Beginning in the 12th century Europe had begun to recover economically and stabilize after the fall of the Roman Empire and the Dark Ages that followed. As a result a lot of money started being spent on ambitious architectural projects that were usually made for the Church.

Notre Dame in Paris was one of these projects, with construction beginning in 1160, the full cathedral was not completed until 1250. However, as parts of the cathedral were completed, church services began to be conducted there, the first of which occurred in 1183.

It was at Notre Dame that two of the earliest composers we have any record of, Leonin and Perotin, were writing music and contributing to the development of polyphony. Leonin and Perotin's music became associated with what history referred to as the Notre Dame School of Polyphony. It's with these two composers that we can begin to trace modern Western music's roots with. Through their efforts, and the efforts of other composers from the Notre Dame School lost to history, they helped establish polyphony as a preferred style of music composition.

Source of Information

The events that Leonin, Perotin, and the Notre Dame School of Polyphony were a part of occurred a long time ago, and due to the chaos and lack of records being kept during the medieval times on music, there is only one source that exists to draw information about Perotin and Leonin.

This source came from a treatise called Anonymous IV. The writer of this treatise most likely lived around the back half of the 13th century. We also know that the writer was an English student studying music at the University of Paris so he was well educated in music. It is in this treatise that we find Leonin and his successor Perotin who are mentioned as important contributors to the music being written at Notre Dame during the 12th and 13th century.

Rhythmic Modes

The six rhythmic modes used by the School of Polyphony at Notre Dame.
The six rhythmic modes used by the School of Polyphony at Notre Dame.

Musical Background

During the 12th century most of the music being written was being done in three different styles: plainchant, organum, and discant.


  • Music being written during and before Leonin and Perotin's time was mostly plainchant, or single line melodies being sung by a choir. Polyphony, where multiple voices sing together by moving independently of one another rhythmically, was just beginning to develop. Plainchant was more common during this time, but that began to change after Leonin and Perotin, as it was gradually replaced by polyphonic music.


  • This musical style can be defined as two or more musical voices singing together but on different notes with pleasant sounding harmonic combinations. There were several types of organum just beginning to be developed during Leonin and Perotin's time, and both composers looked to contribute to the newly developing style.


  • This is an organum style where the rhythm in both voices move using modal rhythms. Modal rhythms are basic rhythmic patterns that are used to make up a larger rhythmic landscape. There were six different modal rhythms in use during this time (see rhythmic modes). This style of composition was specifically developed by the School of Polyphony at Notre Dame.


Leonin (1150's-1201) worked at the Notre Dame cathedral where he was affiliated with the Monastery of St. Victor. Leonin had a Master of Arts degree that he presumably received at the University of Paris. According to Anonymous IV Leonin was the best composer of organum at the cathedral.

Leonin, and something his successor Perotin also did was combine plainchant, organum, and discant into single compositions. This gave their music a different palette to draw different sounds from. The music they wrote became more interesting, with a wider variety of sounds they were able to keep listeners engaged.

While serving at Notre Dame, Leonin compiled the Magnus Liber Organi (a great book of polyphony). This book contained the Graduals, Alleluias, and Office Responsories for major Christian events that occur throughout the year.

It is difficult to discern what Leonin wrote in the book, because the book was frequently being added to by other composers after Leonin had finished writing it. On the whole though, this book offers a look at the music being written by the School of Polyphony at Notre Dame. This book is significant because it shows how plainchant developed with, combined with, and influenced the creation of new polyphonic composition techniques.

Viderunt Omnes

This a copy of the music to Perotin's version of Viderunt Omnes
This a copy of the music to Perotin's version of Viderunt Omnes | Source


Perotin (end of 12th/beginning of the 13th century) is believed to be Leonin's successor at Notre Dame. There is even less information about Perotin's life than Leonin's, but like Leonin he did have a Master of Arts degree. The Anonymous IV treatise claims that Perotin had mastered the discant style, even surpassing Leonin's ability to write it.

However, despite the fact that little is known about Perotin's life, there are complete records of compositions that were solely written by him. Through these we are able to see what Perotin was directly able to contribute to music.

Perotin's contributions to music, for example, provide some of the earliest known well written examples of polyphonic music written for three and four voices. He also provides some of the earliest examples of voice exchanging.

Note: Voice exchanging is where musical voices trade phrases with one another. For example, the top voices sing one musical phrase while the bottom voices simultaneously sing another different musical phrase. Directly after that a new a phrase starts where the bottom voices sing what the top voices were previously singing, while top voices sing what the bottom voices were previously singing.

Contributions to Modern Music

Leonin, Perotin, and the composers from the Notre Dame School contributed greatly to the development of modern music.

The use of modal rhythms in the discant style that the Notre Dame School pioneered called for developing new music notation. The new musical notation for rhythms was the first significant change to musical notation since the time of the Ancient Greeks. These notations also make up some of the rhythmic notations that can be seen in music today.

Perotin was also among the earliest composers who wrote polyphony for three and four voices. Today, four voices is the standard for many choir compositions. By writing many high quality polyphonic compositions Leonin and Perotin subsequently encouraged polyphonic composition. Polyphony would ultimately lead to the creation of harmony which is also in wide use today.

Leonin and Perotin elevated musical art forms in their time. Subsequent composers would try to build upon the music of Leonin and Perotin remembering they went places no one went before.

Recommended Listening:

  • Leonin - Viderunt Omnes
  • Leonin - Dulce Lignum
  • Perotin - Viderunt Omnes
  • Perotin - Alleluia nativitas
  • Perotin - Beata Viscera


  • A History of Western Music - Burkholder

More Articles About the History of Classical Music

Below are some other articles I have written about the history and development of classical music.

Philippe de Vitry and the Ars Nova

  • This article explores the Ars Nova movement in 14th century France that was presumably started by Philippe de Vitry. The Ars Nova movement would see the development of modern rhythmic notation and have a tremendous impact on the way music is notated today.

Palestrina: The Savior of Western Music?

  • Palestrina was an Italian Renaissance composer who would be remembered for his contributions to the development of polyphony in music. This article also explores the long documented claim that Palestrina saved the art of writing polyphonic music from the Council of Trent and the Catholic Church.

The Early History of the Symphony: Origins and Evolving Structure

  • This article explores the early days of the symphony in classical music. It's rise from being a short orchestral overture to becoming the pinnacle of instrumental music has made it one of the most popular genres of classical music listened to today.

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