Die Fledermaus (The Bat) is an operetta composed by Johann Strauss II to a German libretto by Karl Haffner and Richard Genée. The original source for Die Fledermaus is a farce by German playwright Julius Roderich Benedix (1811–1873), Das Gefängnis (The Prison). Another source is a French vaudeville play, Le réveillon, by Henri Meilhac and Ludovic Halévy.
The operetta premièred on April 5, 1874 at the Theater an der Wien in Vienna, and has been part of the regular operetta repertoire ever since. It was performed in New York under Bial at the Stadt Theatre on November 21, 1874, and then in English in London at the Alhambra Theatre on December 18, 1876, with the score heavily adapted by Hamilton Clarke. Its first London performance in the original German was in 1895.
After committing a petty crime, The Baron von Eisenstein is due to start his eight-day jail term. Even though he tells his wife, Rosalinde, he is going to jail, he actually decides to delay jail one day in order to attend a fancy ball at Prince Orlofsky’s with his friend Dr. Falke. Meanwhile, Rosalinde takes advantage of the situation and invites over her lover, Alfred. Confusion ensues when the next day, the prison guard arrives and mistakes Alfred to be the Baron and takes him to prison