(b 29 Jun. 1866; d St Petersburg, 28 Jan. 1896)
Russian dancer, teacher, and inventor of dance notation system. He studied anatomy at St Petersburg University while dancing with the Mariinsky and as a result developed his notations system based on the principles of musical notation which he published as Alphabet des mouvements du corps humain in Paris in 1892. (This was not geared specifically to ballet, though it was used for that purpose.) His system was not published in Russia until after his death and though it was never very widely adopted it was used to notate the Mariinsky classics in St Petersburg. Sergeyev took these notations with him to the West and used them as the basis from which to mount productions of Swan Lake, Sleeping Beauty, etc. in England and in France.