This book explores how the Enlightenment aesthetics of theater as a moral institution influenced cultural politics and operatic developments in Vienna between the mid-eighteenth and early nineteenth centuries. The idea that vernacular theater should cultivate the moral sensibilities of its German-speaking audiences became prominent during the reign of Empress Maria Theresa. The imperial government promoted good morals in theatrical performances through the institution of theater censorship, and German-opera authors cultivated intensely didactic works (such as Die Zauberflöte and Fidelio) that eventually became the cornerstones for later developments of German culture.