Taking the Boethian understanding of the relation between the musicus and cantor as his point of departure, Jacobus – the author of the Speculum musicae – develops this relation in light of new ecclesiastical realities and the Aristotelian understanding of the relation between theory and practice. Without entirely abandoning an allegiance to the priority of theory over practice and the corresponding embodiments of these categories in the musicus and cantor, Jacobus redefines these terms to create a new threefold taxonomy: the Boethian musicus who understands but does not perform or compose, the practicus musicus who both understands and practises within an ecclesiastical context (and is the equivalent of the peritus cantor), and the cantor who sings without understanding. These developments within the Speculum musicae follow attempts by earlier authors to negotiate the relation between the heritage of antiquity and the cantus tradition of musical practice within liturgical contexts. Jacobus's solution also differs from solutions offered by contemporary and later authors.
