Suetonius wrote The Twelve Caesars in the early second century: short lives of Rome's first emperors, Julius Caesar through Domitian. This is Tiberius, who took the throne after Augustus in AD 14. He came to it already a great general of the Rhine and Danube, the German and Balkan frontiers.

He leaves it as a rumor from Capri, an island off Naples. He never quite says what he means. Sejanus rises as prefect of the Guard — the emperor's household troops — and partner in fear. Treason trials, maiestas, teach the aristocracy the price of a sentence. The death of Germanicus, a popular young commander, feeds talk of poison. Early care in running the empire is admitted, then buried under cruelty and sexual infamy. The island becomes a picture of a tyrant who will not show his face. Macro, another prefect, manages the ugly end. Caligula follows, Germanicus's son.