Complex sentence: Arthur Saint-Léon (September 17,1821 in Paris--September 2,1870) was the "Maître de Ballet" of St. Petersburg Imperial Ballet from 1859 until 1869 and is famous for creating the choreography of the ballet "Coppélia".
Split into simpler sentences: Arthur Saint-Léon (September 17,1821 in Paris--September 2,1870) was the "Maître de Ballet" of St. Petersburg Imperial Ballet from 1859 until 1869. He is famous for creating the choreography of the ballet "Coppélia".