The Sergeyev Collection is a collection of choreographic notation, music, designs for décor and costumes, theatre programs, photos and other materials that document the repertory of the Imperial Ballet (precursor of the Kirov/Mariinsky Ballet) of St. Petersburg, Russia at the turn of the 20th century. The majority of the choreographic notations document with varying degrees of detail the original works and revivals of the renowned choreographer Marius Petipa, who served as "Premier Maître de ballet" of the St. Petersburg Imperial Theatres, as well as notation and music documenting the ballets of Lev Ivanov, who served as second "Maître de ballet". Also included in the collection are choreographic notation documenting dances from various operas by both Petipa and Ivanov, respectively.