Montpellier Codex

While the music in the Codex is anonymous, a number of attributions can be made, either because of concordances in other manuscripts or on the basis of stylistic similarity, to Pérotin (from fascicle 1), Petrus de Cruce, Adam de la Halle, Guillaume d'Auvergne, and Philippe le Chancelier.

While fascicle 1 consists of sacred polyphony, mostly from the Notre Dame school, the largest body of music in the Codex is the collection of French courtly love motets.

Recently, however, Michael Lanford has noted that "of the 148 double and triple motets in fascicles two through five of the Montpellier Codex, 114 have repeating colores."

After analyzing several motets, he also demonstrates that "each of Richard Hoppin's 'three isorhythmic procedures' which inform 'future developments of the form' can be found in select tenors from the Old Corpus [of the Montpellier Codex], often in ways that demonstrate resourceful approaches to managing the rhythmic modes."

For these reasons, Lanford contends that "by glossing over the presence of isorhythmic techniques in thirteenth-century motets, such as those found in fascicles two through five of the Montpellier Codex, scholars have thus limited the appellation of 'isorhythm' using criteria that is well-reasoned, yet perhaps unnecessarily restrictive.