What is Ludwig van Beethoven's only opera?
Fidelio. Beethoven struggled to produce an appropriate overture for Fidelio, and ultimately went through four versions. The libretto, with some spoken dialogue, tells how Leonore, disguised as a prison guard named "Fidelio", rescues her husband Florestan from death in a political prison. Bouilly's scenario fits Beethoven's aesthetic and political outlook: a story of personal sacrifice, heroism, and eventual triumph.