The theory and practice of a-modes in Glarean’s "Dodecachordon", 1547

The number of compositions with finals on A, possible modal interpretations of Acadences and the potential pitch space available in the gamut (specifically G-mi) had increased substantially by the early sixteenth century. Lacking the tools and a vocabulary sufficient to describe these phenomena, theoretical attempts to relate polyphony characterized by ambiguous relationships facilitated by "A la mi re" to traditional expositions of the monophonic octenary modal system were often contradictory or summary at best. By means of the introduction of an Aeolian mode and its plagal counterpart in his "Dodecachordon" of 1547, Heinrich Glarean hoped to systematically describe and to settle the difficulties theorists before him had encountered in trying to account for a repertory that was increasingly focused on "A la mi re". By invoking the established musical repertoire of the Roman liturgy and famous contemporaneous composers who employed pieces in which "A la mi re" proved so much of a focal point as to be considered a modal final, and by addressing his audience in an experiential manner as educated listeners who have the ability to derive rhetorical meaning from a given passage, Glarean not only managed to bring theory in closer alignment with practice but ensured that a potentially disruptive thesis in which the octenary tradition was supplanted by a dodecaphonic structure would fall on relatively uncritical ears. Glarean's A-modes did not only account for a rapidly growing repertoire in which finals on A figured prominently, however, but served to strip the modal mutation between D- and E- final modes (i.e., "ab Dorian ad Phrygian") of its disturbing character by theoretically sanctioning Dorian to Phrygian mutation through its affinity to A. Despite its assimilation into the evolving style, this once jarring mutation still had the potential to disturb in certain contexts, but this was largely owing to its historical references (first described by Erasmus in 1513 as the combination of incongruous elements) rather than its actual modal character. This thesis attempts to describe the relationship between Dorian and Phrygian modalities through Glarean's understanding of the A-modes by examining late fifteenth- and early sixteenth-century changes in tonal focus, solmization practices and the expansion of the gamut.Arts, Faculty ofMusic, School ofGraduat