This paper treats plagiarism as performance and Angelo Berardi as a virtuoso. Berardi (1636–94), an active composer and musician, is remembered for his half dozen musical writings. Beginning with a discussion of previously lost or unknown writings by Berardi and his mentor Marco Scacchi, I demonstrate that Berardi composed his prose works through a highly self-conscious process of borrowing. More broadly, Berardi's case opens a window onto the construction of musical texts and simultaneously complicates them as straightforward sources of musical information. Musicians used—and appropriated—the written word to craft and project personae in response to epistemological and social disadvantages: theory outranked practice and theorists outranked practitioners. In style, technique, and content Berardi is representative of musician-authors who presented themselves as gentlemen rather than musicians, adopted the style and tone of Italian academies and erudites, and favored more speculative matters (musical science, antiquarianism, friendship, combinatorics), sometimes at the expense of practical ones. They pursued metaphysical and quadrivial questions now disregarded as irrelevant. I argue that, on the contrary, such writings reveal most precisely, at their most “irrelevant” and derivative, a musical and even mental world not quite congruent with current interest in its musical artifacts.