Complex sentence: Nijinsky is immortalized in numerous still photographs, many of which were made by E.O. Hoppé, who extensively photographed the Ballets Russes London seasons between 1909 and 1921.
Split into simpler sentences: Nijinsky is immortalized in numerous still photographs, many of which were made by E.O. Hoppé. He photographed the Ballets Russes London seasons extensively between 1909 and 1921.