Lev Ivanov (lyĕf ēvä´nôf), 1834–1901, Russian dancer, teacher, choreographer, and ballet-master. Ivanov was assistant to chief ballet-master Marius Petipa at the Imperial St. Petersburg Theatres and was instrumental in the development of the classic romantic ballet in Russia. When Petipa fell ill, Ivanov created the choreography for The Nutcracker (1892) to the music of Tchaikovsky. After Tchaikovsky's death, the previously unsuccessful Swan Lake (1877) was revised with choreography by Petipa and Ivanov, each doing alternate acts in varying styles. His other major works include revivals or stagings of La Fille Mal Gardée, The Enchanted Forest, The Magic Flute, and Cinderella. Ivanov sought a closer relationship of dance and music, thereby influencing the work of later choreographers, including Michel Fokine.