When he began his engagement at the Theater an der Wien, Beethoven also committed himself to writing an opera for the venue. For it, Joseph Sonnleithner translated the popular libretto Léonore ou L’amour conjugal by Jean Nicolas Bouilly. The genre of the rescue opera reflected the desire for freedom and justice. Accordingly, Beethoven’s Fidelio also deals with the political prisoner Florestan who has been incarcerated by his adversary, Governor Don Pizarro. Disguised as a man and using the alias “Fidelio”, Florestan’s wife Leonore wins the trust of the gaoler Rocco, suspecting that it is in his cells that her husband is being held. She succeeds in rescuing him from prison at the last moment. The earliest extant version of Beethoven’s only opera has three acts, and neither its music nor its plotting are fully developed. That Fidelio was performed only twice following the premiere probably had more to do with the audience: one week before the premiere on 20 November 1805, Napoleon and his troops occupied Vienna. Consequently, the city, and the audience at the Theater an der Wien, was full of French soldiers who, in the middle of their European campaign, were probably not especially receptive to the German text and the message of liberation that is central to the opera.