In that time letters flourished at Paris. Never before in any time or in any part of the world, whether in Athens or in Egypt had there been such a multitude of students. The reason for this must be sought not only in the admirable beauty of Paris; but also in the special privileges which King Philip and his father before him conferred upon the scholars. In that great city the study of the trivium and the quadrivium... [was] held in high esteem. But the crowd pressed with a special zeal about the chairs where Holy Scripture was taught, or where problems of theology were solved.

Magister Leoninus was the best composer of organum, who made the Magnus liber organi de Gradali et Antiphonario in order to increase the divine service. This was in use until the time of the great Perotinus who shortened this book and made many better clausulae or puncta [substitute sections], since he was the best composer of discantus and better than Leoninus, although he cannot be said to reveal the subtlety of [Léonin’s] organum. This Magister Perotinus wrote the best quadrupla [four-part organa] such as Viderunt and Sederunt with an abundance of ‘colours’ in the art of harmonic music... The book or books of Magister Perotinus were in use both in the choir of the church of Notre Dame in Paris until the time of Magister Robertas de Sabilone, and from his time until the present day....

Certain disciples of the new school, much occupying themselves with the measured dividing of time, display their method in notes which are new to us, preferring to devise ways of their own rather than to continue singing in the old manner; the music, therefore, of the divine offices is now performed with semibreves and minims, and with these notes of small value every composition is pestered. Moreover, they truncate the melodies with hocket, they deprave them with discantus, sometimes even they stuff them with upper parts made out of secular song... We now hasten therefore to banish these methods... and to put them to flight more effectually than heretofore, far from the house of God.

This sort of song should not be performed before ordinary people because they do not notice its fine points nor enjoy listening to it, but before learned people and those on the lookout for subtleties in the arts.