Concepts borrowed from classical rhetoric have been frequently applied to the analysis and performance of eighteenth-century music since the 1970’s. Part of the justification for this scholarly and musical practice is the evidence of ‘musical rhetoric’ found in period theory. A more controversial premise is the high cultural status and the ubiquitous presence of rhetoric during this period. This contradicts an established consensus that during the Enlightenment rhetoric was in decline, surrendering much of its authority to aesthetics. This essay offers a broader perspective on this controversy, examining both the evolution of the disciplinary borders between rhetoric and aesthetics, and the interdisciplinary reappraisal of rhetoric in the late twentieth century.