Fidelio (originally named Leonore, oder Der Triumph der ehelichen Liebe; English: Leonore, or The Triumph of Marital Love), Op. 72, is a German opera with spoken dialogue by Ludwig van Beethoven, his only opera. The German libretto was originally prepared by Joseph Sonnleithner from the French of Jean-Nicolas Bouilly and the work premiered at Vienna's Theater an der Wien on 20 November 1805. The next year Stephan von Breuning helped shorten the three acts to two. After further work on the libretto by Georg Friedrich Treitschke a final version performed at the Kärntnertortheater on 23 May 1814. By convention both of the first two versions are referred to as Leonore.