The first performance of the ballet was held as a double premiere together with Tchaikovsky's last opera, Iolanta, on 18 December [O. S. 6 December] 1892, at the Imperial Mariinsky Theatre in Saint Petersburg, Russia. Although the libretto was by Marius Petipa, who exactly choreographed the first production has been debated. Petipa began work on the choreography in August 1892; however, illness removed him from its completion and his assistant of seven years, Lev Ivanov, was brought in. Although Ivanov is often credited as the choreographer, some contemporary accounts credit Petipa. The performance was conducted by Riccardo Drigo, with Antonietta Dell'Era as the Sugar Plum Fairy, Pavel Gerdt as Prince Coqueluche, Stanislava Belinskaya as Clara, Sergei Legat as the Nutcracker-Prince, and Timofey Stukolkin as Drosselmeyer. Unlike in many later productions, the children's roles were performed by real children – students of the Imperial Ballet School in Saint Petersburg, with Belinskaya as Clara, and Vassily Stukolkin as Fritz – rather than adults.