Swan Lake is a ballet, op. 20, by Pyotr Ilyich Tchaikovsky, composed in 1875–1876. The scenario, initially in four acts, by Vladimir Begichev and Vasiliy Geltser was fashioned from Russian folk tales as well as an ancient German legend. It 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.