The witches in Shakespeare’s Macbeth equivocate between the demons of random malevolence and ordinary (if exceptionally nasty) old women; and both King James I, whose book on witchcraft may have influenced Shakespeare, and A. W. Schlegel, whose essay on Macbeth certainly influenced Verdi, also stress this ambiguity. In his treatment of Lady Macbeth, Verdi uses certain musical patterns associated with the witches; and like the witches, who sound sometimes tame and frivolous, sometimes like incarnations of supernatural evil, Lady Macbeth hovers insecurely between roles: she is a hybrid of ambitious wife and agent of hell.

Scholarly consensus denies a real connection between ancient tragedy and early opera because music historians have measured early operas against an idealised conception of Attic tragedy. However, the pioneers of opera were seeking to revive a Euripidean style of musical tragedy as it was performed in the ‘decadent’ theatres of the Hellenistic era. Euripides's tragedies established conventional relationships between musical expression and the representation of the passions. Baroque opera is seen as a strongly complex reading of a set of Euripidean tragedies that enjoyed favour in the Hellenistic era but fell from critical grace in the nineteenth century. These plays hold the key to opera's tragic pretensions; the esteem they long enjoyed should prompt us to reconsider the spirit of tragedy and the nature of catharsis.

The final performances of castrato Giovanni Battista Velluti in London in the late 1820s constitute a particularly rich vantage point from which to explore why the castrato was eventually forced from the operatic stage. What does this historical moment have to say about shifts in vocal style and audience expectations? Why did the question of castration become so loaded under ‘Romantic’ conditions? This article constructs a speculative theoretical framework by bringing together recent insights in the history of vocal science, histories of gender and subjectivity, the history of listening and opera studies. Velluti's hostile reception in the London press is surveyed in detail, alongside a historically informed examination of his vocal manner. Evidence suggests that the castrato quickly became an unthinkable figure, falling from grace in the wake of embodied conceptions of vocality and ‘natural’ expression, newly dominant ideas that projected him beyond prevailing notions of human nature.