Swan Lake (Russian: Лебединое озеро, Lebedinoye ozero) ballet, op. 20, by Pyotr Tchaikovsky, composed 1875–1876. The scenario, initially in four acts, was fashioned from Russian folk tales  and tells the story of Odette, a princess turned into a swan by an evil sorcerer's curse. The choreographer of the original production was Julius Reisinger. The ballet received its premiere on March 4 [O.S. February 20] 1877 at the Bolshoi Theatre in Moscow, billed as The Lake of the Swans. Although it is presented in many different versions, most ballet companies base their stagings both choreographically and musically on the 1895 revival of Marius Petipa and Lev Ivanov, first staged for the Imperial Ballet on January 15, 1895, at the Mariinsky Theatre in St. Petersburg. For this revival, Tchaikovsky's score was revised[clarification needed] by the St. Petersburg Imperial Theatre's chief conductor and composer Riccardo Drigo.