Fidelio 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. With its underlying struggle for liberty and justice mirroring contemporary political movements in Europe, such topics are typical of Beethoven's "middle period". Notable moments in the opera include the "Prisoners' Chorus" ("O welche Lust"—"O what a joy"), an ode to freedom sung by a chorus of political prisoners, Florestan's vision of Leonore come as an angel to rescue him, and
Rescue opera to "Fidelio" is Rossini's "Torvaldo e Dorliska" of 1815. Bedřich Smetana's "Dalibor" (1868), which contains no spoken dialogue and which bears marks of Wagnerian influence, has nonetheless been called a rescue opera, in part because of its political themes. Rescue opera was primarily a product of the French Revolution. The social changes of the period meant that opera must now appeal to the masses, and post-aristocratic, patriotic, idealistic themes—such as resistance to oppression, secularism, the political power of individuals and of people working together, and fundamental changes to the status quo—were popular. The Terror influenced stories of fear and imprisonment;