In 1607 Claudio Monteverdi’s younger brother, Giulio Cesare, published his Dichiaratione, arguably the most significant document of the famous and influential polemic known as the Artusi-Monteverdi controversy. He there attempted to rebut Giovanni Maria Artusi’s criticism of the technical “licenses”—especially with regard to dissonance treatment—that the great composer had sought to justify as essential elements of the new approach to text setting that he called the seconda pratica. In support of his argument, Giulio Cesare quotes passages from Plato’s Republic in order to claim the great philosopher’s authority for his brother’s revolutionary musical poetics. As I show in this study, the Platonic pronouncements concerning what the Monteverdis call melodia, that is, song (melos), provide Giulio Cesare with virtually the whole of his implicit argument for the artistic validity of Claudio’s subversive compositional practices.
The article’s principal aim, however, is to demonstrate that Giulio Cesare exploits a lexical peculiarity in Ficino’s Latin translation of the Republic to misrepresent Plato’s thought on a point of great importance to the philosopher: the power of song to influence a people’s ēthos, their ethical or moral character. Ficino’s idiosyncratic rendering in the crucial passage of ēthos tēs psychēs as affectio animi (“affection of the soul”) enables, and indeed invites, Giulio Cesare to elide the true object of Plato’s concern and instead implicitly associate the philosopher’s dicta regarding the ethical force of melos with what the Dichiaratione identifies as the goal of the seconda pratica: “moving the affections of the soul.”