On modulation in Eastern and Western chant

ABSTRACT In his Epistola de harmonica institutione ( c. 900 CE), Regino of Prüm names fourteen antiphons that he calls nothae – that is, ‘degenerate and illegitimate – that begin in one mode, are yet another in the middle, and end in a third’. These antiphons represent two different types of modulation: one diatonic, the other resulting from systemic transposition brought about by chromatic alteration. A rationale for both types of modulation is offered by the Musica and Scolica enchiriadis , respectively, both dating to the second half of the ninth century, with the Scolica providing a theory of vitia , or ‘corruptions’, to accommodate chants modulating by means of chromatic alteration. Modulation likewise played an important role in Eastern chant. Gerda Wolfram has shown that both diatonic and chromatic modulation can be documented in the earliest manuscripts of Byzantine chant, namely those dating to the tenth century. Indeed, the Hagiopolites , the oldest preserved Byzantine treatise on music (twelfth century CE), discusses chromatic modulation via what are called phthoraí (‘corruptions’), like the vitia in the West, and the papadikaí , or singers’ manuals, explicate the theory of diatonic modulation called ‘ parallagḗ ’. This article illustrates both phthorá and parallagḗ with an exercise from the treatise on church music by Akakios Chalkeopulos ( c. 1500 CE), and concludes that not just the nomenclature and intonation formulas of the Byzantine modes, but also the technique of modulating within a single chant were features shared by both Eastern and Western chant already in the earliest stages of their respective written traditions.