Fidelio (; German: [fiˈdeːlio]), originally titled Leonore, oder Der Triumph der ehelichen Liebe (Leonore, or The Triumph of Marital Love), Op. 72, is the sole opera by German composer Ludwig van Beethoven. The libretto was originally prepared by Joseph Sonnleithner from the French of Jean-Nicolas Bouilly. The opera premiered at Vienna's Theater an der Wien on 20 November 1805. The following year, Beethoven's friend Stephan von Breuning rewrote the libretto, shortening the work from three acts to two.
https://en.wikipedia.org/wiki/Fidelio