Swan Lake (Russian: Лебеди́ное о́зеро, romanized: Lebedínoje ózero, Russian pronunciation: [lʲɪbʲɪˈdʲinəjə ˈozʲɪrə]), Opus 20, is a ballet composed by Pyotr Ilyich Tchaikovsky between 1875 and 1876. The original production premiered at the Bolshoi Theatre in Moscow on 4 March 1877 (20 February Old Style), with choreography by Julius Reisinger. The ballet, initially conceived in two acts, is based on Russian and German folk tales and tells the story of Princess Odette, who is transformed into a swan by the sorcerer Von Rothbart.
The initial reception was lukewarm, with criticism directed at various elements of the production. Despite this, Swan Lake has become one of the most frequently performed ballets worldwide.