Fidelio, Playbill of the world premiere, Vienna, Kärntnertortheater, May 23, 1814
Fidelio is an opera in two acts by Ludwig van Beethoven. It is Beethoven's only opera. The German libretto is by Joseph Sonnleithner based on a French story. The opera tells how Leonore, disguised as a prisonguard called "Fidelio", rescues her husband Florestan from death in a political prison.