The infamous emperor Caligula ruled Rome from A.D. 37 to 41 as a tyrant who ultimately became a monster. An exceptionally smart and cruelly witty man, Caligula made his contemporaries worship him as a god. He drank pearls dissolved in vinegar and ate food covered in gold leaf. He forced men and women of high rank to have sex with him, turned part of his palace into a brothel, and committed incest with his sisters. He wanted to make his horse a consul. Torture and executions were the order of the...