Roman Denarius of Caligula, c.37 to 41 A.D. NGC VF. Caligula (Gaius Julius Caesar Augustus Germanicus), 31 August 12–24 January 41, was Roman Emperor from 37 to 41. A member of the Judio-Claudian dynasty, his father was Germanicus and he was the great-nephew and adopted son of Tiberius. The young Gaius was given the nickname “Caligula” (“little soldier’s boot”) by his father’s soldiers when he accompanied him in Germania. While a teenager, his mother and older brothers were arrested and died horrible deaths due to the intrigues of the Praetorian Prefect Sejanus. From 32 onward he lived on the Isle of Capri with the emperor Tiberius and was his heir, along with Tiberius Gemellus. Caligula took power in 37, and the senate gave him all the powers of imperial office, hailing him princeps (“first citizen”) and voiding Gemellus’ claim to joint rule.
Caligula was very popular. He ended Tiberius’ treason trials, paid quite generous bequests to the Roman citizenry and a sizable bonus to the praetorian guard. But six months later he became quite ill. After that he was a very different man. The Roman historian Suetonius tells us that Caligula suffered from epilepsy since childhood. That, or something else, violently changed his state of mind, making him completely irrational, with delusions of grandeur and divinity. Caligula had four wives, and it was said that he had incest with his three sisters. He had difficulty sleeping, getting only a few hours of sleep and having horrible nightmares. He would wander around the palace waiting for sunrise. Caligula had people put to death with no trial, including Gemellus and his principal supporter, praetorian prefect Macro. He ordered an alter to be build to himself, and proposed that statues of himself be placed in synagogues. He introduced new taxes to help pay for his personal projects. In 39 he announced the return of the treason trials, which had terrorized Rome in the last years of Tiberius’ rule. He kept his favorite racehorse, Incitatus, inside the palace. Dinner guests were invited in the horse’s name, and the horse joined the emperor and guests for dinner. More people were executed, his sisters were banished and he seized their property, and he planned military campaigns in German lands and Britain that never took place. Conspiracies developed to get rid of Caligula. On January 24, 41, three praetorian guardsmen assassinated the unhinged emperor.