Archaeologist Marialetizia Buonfiglio says the image is the only documentation of horses involved in the ancient entertainment, which included popular chariot races.

Events include bareback riding, bull riding, wild horse racing, barrel racing, bull-dogging, wild cow milking, a chariot race, convict poker and Guts and Glory.

Its ambitions were grand: the film’s producers had wanted to shoot chariot race scenes in the actual Circus Maximus until Italian officials called it off.