Russian dance and the expense of staging opera. The idea of mixing the mythical Firebird with the unrelated Russian tale of Koschei the Deathless possibly came from a popular child's verse by Yakov Polonsky, "A Winter's Journey", which includes the lines: And in my dreams I see myself on a wolf's back Riding along a forest path To do battle with a sorcerer-tsar (Koschei) In that land where a princess sits under lock and key, Pining behind massive walls. There gardens surround a palace all of glass; There Firebirds sing by night And peck at golden fruit. Benois collaborated with the choreographer Michel Fokine, drawing from several books of Russian fairy tales including the collection of Alexander Afanasyev, to concoct a story involving the Firebird and the evil magician Koschei. The scenery was designed by Aleksandr Golovin and the costumes by Léon Bakst. Diaghilev first approached the Russian composer Anatoly Lyadov in September 1909 to write the music. There is no evidence that he ever accepted the commission, despite the anecdote that he was slow to start composing the work. Nikolai Tcherepnin composed some music for the ballet (which he later used in his The Enchanted Kingdom), but withdrew from the project without explanation after completing only one scene. After deciding against using Alexander Glazunov and Nikolay Sokolov, Diaghilev finally chose the 28-year-old Stravinsky, who had already begun sketching the music in anticipation of the commission. Stravinsky would later remark about working with Fokine that it meant "nothing more than to say that we studied the libretto together, episode by episode, until I knew the exact measurements required of the music." Several ideas from Rimsky-Korsakov were used in The Firebird, most notably in the use of leitmotifs. Rimsky-Korsakov used ascending thirds as leitmotifs for villains in his operas Mlada, Pan Voyevoda, and Kashchey the Deathless, and Stravinsky harmonically extended this idea to build the harmonies in Firebird. The piano score was completed on 21 March 1910 and was fully orchestrated by May, although not before work was briefly interrupted by another Diaghilev commission: an orchestration of Grieg's Kobold, Op. 71, no. 3 for a charity ball dance featuring Vasily Nijinsky. Soon thereafter, Diaghilev began to organize private previews of The Firebird for the press. French critic Robert Brussel, who attended one of these events, wrote in 1930: The composer, young, slim, and uncommunicative, with vague meditative eyes, and lips set