Conference Agenda

As most of us know, the theory of "modes, which are also called τρόποι or τόνοι," presented in Boethius's De institutione musica shortly after 500 CE, became the foundation for the medieval and Renaissance theory of the church modes: protus, deuterus, tritus, tetrardus, and later Dorian, Phrygian, Lydian, Mixolydian and their plagals. As we also know, however, the mature system of the church modes was actually founded in part upon a misunderstanding of Boethius´s presentation of the ancient Greek τόνοι or modes by the principal author of the ninth- or early tenth-century treatise Alia musica. But was it really?

This paper will demonstrate that the main author of the Alia musica, and indeed other authors of music treatises from the ninth century of the Common Era onwards, could not have understood the τόνοι as presented by Boethius. Boethius simply did not give them enough information to do so.

Boethius begins his treatment of the modi or τόνοι in Book IV, chapter 15 of his Musica with the famous statement: "Out of the species of the consonance of the diapason arise what are called modi, which are also called τρόποι or τόνοι" - a clear reference to the theory of the τόνοι presented by Klaudios Ptolemaios in Book 2 of his Harmonicá (2nd century CE), a treatise Boethius knew well; the fifth book of his Musica is a translation of the first book of Ptolemy´s work. Ptolemy's theory is based on the species of the diapason displayed between fixed pitches by transpositions of the ancient Greek systema teleion, and depends upon the distinction between thesis and dynamis to orient the reader. While Boethius does present the theory of the τόνοι or modi as transpositions of the systema teleion, he does not explain how to identify the τόνoς of each transposition via species of the diapason, despite his assertion quoted above. Had he done so by taking two simple steps, the history of the modes in Western music would be completely different from the one we have known for over a thousand years.