The Petronian Motet: Baby Steps

Album: Music of the Gothic Era
Track: "Aucun ont trouvé" (Track #2 on disk 2)
Composer: Petrus de Cruce
Instruments: 2 voices, 1 fiddle
Musical form: Motet
Year: ~1290

Any politician will tell you that tradition can often be a sizable impediment to progress, even when progress is the universal goal. So it goes with music as well. Suppose you decided one day that you were going to write a song about... I don't know, your favorite piece of dishware. Any song you would sit down to write would likely be some combination of music you had already heard, even if that music had not itself been about dishware (most likely it wasn't). This applies equally in the 21st century as in the 13th century, but imagine further if all of the music you had heard previously had been performed (and likely written) within 100 miles of your house. Even further, imagine that when you want to write this music down (there are no recording devices onhand), you need to write within a preexisting rhythmic structure if anyone is going to be able to translate what you have written into a performance. In other words, you have two choices. You either write your song the traditional way or you invent your own notation for a new rhythmic structure, write a treatise explaining that notation, and then write a song within this new untested rhythmic structure.

Given these barriers, it should be no surprise that it took over a century to break from the traditions established by the Notre Dame School of Polyphony, particularly when the latter had exploited them so effectively. Nevertheless, two medieval composers, Petrus de Cruce and Philippe de Vitry, chose the more difficult of the two options described above. In this case, the tradition was the rhythmic modes, structures that had at that point become embedded in the musical notation. Phlippe de Vitry essentially started from scratch and I will discuss his work in a later entry. Petrus de Cruce did not eliminate the rhythmic modes, but in his treatise, Ars cantus mensurabilis, he invented a notation that allowed for an arbitrary number of rhythmic subdivisions within each mode repetition. For example, if I was writing within the first rhythmic mode, I could have the lower voice keep a "long - short" rhythm at an arbitrarily slow tempo while the highest voice filled the gaps with an elaborate melody many notes in length. Any motet that used this technique (and accompanying notation) was called a "Petronian motet," named after Petrus de Cruce himself.

The example given, "Aucun ont trouvé", has only two voices and works primarily within the first rhythmic mode. The Petronian technique certainly makes the piece sound more "free", but at the expense of substance. The upper voice sounds like it's performing a monologue, while the lower voice carries a rhythm, performed in a slow drawl, that often gets lost in the flowery melody. Although there is no doubt in my mind that the technique could be used effectively, this Petronian motet really does feel like a short-term fix to a long-term problem -- like treating hemorrhagic fever with band-aids. Well, it's not really anything like that, but bigger changes (and better similes) are to come. Stay tuned.

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