A Roman graveyard has been dug up in York. The skeletons all belonged to tall, strong men — and most are headless. Were they gladiators killed in the arena or victims of a deranged dictator?Like nobody else before or since, Caracalla had it coming. On April 8, AD217, four days after his 29th birthday, appropriately on his way to a Moon Temple in modern-day Turkey, this irredeemable lunatic dismounted from his horse, pulled down his breeches and surrendered to the demands of diarrhoea. It was one of his own bodyguards who stepped forward and stabbed him to death. Even for...