This recording of Ensemble Organum in Guillaume de Machaut's Messe de Notre-Dame -- a pivotal piece, as it is the earliest complete polyphonic mass setting by a named Western composer of prominence -- was destined to enter the field as one of the most controversial early music recordings ever. Marcel Pérès and his group decided to vocally ornament the music, a feature for which there is no indication in the surviving sources in the Mass itself, nor historic support in what few treatises we have from Machaut's century, the fourteenth. If the specific type of ornaments the Ensemble Organum introduces into this music can be identified, perhaps a parallel can be drawn to Arabic singing or to some of the keyboard ornaments found in the Codex Faenza, a source that at it's earliest possible point origin can be dated to about the time that Machaut died. Although it is a four-voice mass, Pérès opts for a very large component of singers, resulting in a very full, rich sound, although the singing is deliberately made a little rough, perceptibly "medieval" in tone, and a little unbeautiful in comparison to the vocally pristine approach commonly employed in early Renaissance music. Such practice is historically nearby to this mass, but understood from what historic sources there are to be different in the essentials.
The sum quotient is, although we have this mass and can read its notation, we cannot really know what Machaut intended it to sound like; there is not enough support material outside of its sources to tell us that. Ensemble Organum's version has a very grave interpretation that emphasizes the low voices and takes a very flexible approach to rhythm; even though we cannot call it "authoritative," it certainly feels that way. The recording is gloriously well made within a cathedral ambience, and all of the appropriate chant passages are taken, stretching the five movements of Machaut's mass out to nearly an hour. Listeners truly interested in Machaut and this seminal masterwork really should know this recording, whether or not they like it; most viable alternatives are more located in the expected realm of interpretation, but are not so passionately devoted to exploring the possibilities of Machaut's Messe de Notre-Dame as this.