The Julio-Claudian Dynasty: The First Family of Rome

For almost a century, from 27 BCE to 68 CE, the Roman world was ruled by a single extended family. They were bound together by blood, by adoption, and by marriage, descending either from the gens Julia of Julius Caesar or the gens Claudia of Livia Drusilla, the wife of Augustus. Together they ruled as the first dynasty of the Roman Empire, and their combined reign is known to history as the Julio-Claudian dynasty. Five emperors carried the name: Augustus, Tiberius, Caligula, Claudius, and Nero. Three of them were murdered or driven to suicide, one was probably poisoned, and only the first died of natural causes.

The dynasty is also the story of an experiment in government. When Augustus took power, there was no such thing as a Roman emperor. The Republic had stood for almost five centuries, and Augustus was determined to rule while preserving its forms. The system he invented — called the Principate — would outlast his dynasty by three centuries, but the Julio-Claudians themselves nearly destroyed it twice, in the madness of Caligula and the tyranny of Nero. For a broader overview of all the emperors, see Roman Emperors.

The Family Tree

The Julio-Claudians were, by the standards of Roman aristocrats, an extremely intermarried family. Augustus himself was born Gaius Octavius, the grandnephew and adopted son of Julius Caesar. He married Livia Drusilla, who already had a son, Tiberius, by her first husband. Augustus forced Tiberius to marry his own daughter Julia, and to adopt Augustus’s nephew Marcellus as his heir. When Marcellus and then both of Augustus’s grandsons died young, Augustus was forced to fall back on his stepson Tiberius.

Tiberius’s heir was his own nephew Germanicus, the popular general who died under suspicious circumstances in 19 CE. Germanicus’s son became Caligula, and Caligula was succeeded in turn by his uncle Claudius, the brother of Germanicus. Claudius was followed by Nero, the son of his fourth wife Agrippina and her first husband, the Domitius Ahenobarbus whom Nero took as a surname. The dynasty ended in 68 CE when Nero, childless and friendless, killed himself in a freedman’s villa outside Rome.

Augustus: The Founder (27 BCE – 14 CE)

Augustus (born Gaius Octavius, 63 BCE – 14 CE) was nineteen years old when he heard that Caesar had been assassinated on the Ides of March, 44 BCE, and that he had been named the dictator’s heir. He spent the next thirteen years fighting a civil war against the assassins Brutus and Cassius and then against Mark Antony. The war ended at the Battle of Actium in 31 BCE, where his admiral Agrippa destroyed the Egyptian fleet of Antony and Cleopatra. A year later Antony and Cleopatra both died in Alexandria, and Octavian was the unchallenged master of the Roman world.

In 27 BCE, the Senate granted him the honorific name Augustus, “the revered one.” The old Republic was over, though Augustus was careful to maintain its forms. He ruled as princeps, “first citizen,” combining in his own person the consulship, the tribunician power, and the proconsular command over the military provinces. He reorganized the army into a professional standing force of twenty-eight legions, paid for by a permanent treasury of his own (the aerarium militare). He reformed the administration of the provinces, beautified Rome with marble temples and porticoes, and produced a written constitution for the empire that historians call the Principate.

The Pax Romana — the two centuries of relative peace that the early empire enjoyed — is often called the Pax Augusta in his honor. For a deeper look at the man, see the biography of Augustus. Augustus died at Nola in 14 CE, in the same room where his father had died. His last words, recorded by Suetonius, were a request that his friends applaud his exit from the mime of life.

Tiberius: The Reluctant Emperor (14 – 37 CE)

Tiberius (42 BCE – 37 CE) had not wanted to be emperor. He was already in his mid-fifties when Augustus died, and he had been made heir only after the deaths of every other candidate. He was a brilliant general who had spent years fighting in Pannonia, Germany, and Illyricum. His first years on the throne were competent and even popular: he ended the great mutiny of the legions on the Rhine, refused to be called dominus, “master,” and governed the empire through the Senate as Augustus had done.

After the death of his son Drusus in 23 CE, however, Tiberius changed. He withdrew to the island of Capri in 26 CE and left the government in the hands of his praetorian prefect, Sejanus. Sejanus spent the next five years accumulating power, executing senators on flimsy charges of treason, and allegedly planning to seize the throne. Tiberius, in his island retreat, grew increasingly paranoid. In 31 CE, having finally become convinced of Sejanus’s treason, he had him arrested and executed along with his entire family and many of his supporters.

The last years of Tiberius were dominated by treason trials and the imperial spymaster. The emperor himself became ever more cruel and suspicious, although modern historians have noted that the picture we have of him comes almost entirely from senatorial sources who had reason to hate him. He died at Misenum in 37 CE, reportedly smothered in his bed by the praetorian prefect Macro so that Caligula could take the throne.

Caligula: The Mad Emperor (37 – 41 CE)

Caligula (born Gaius Caesar, 12 – 41 CE) was the great-great-grandson of Augustus and the son of the popular general Germanicus. His childhood nickname, Caligula — “little boot” — came from the miniature soldier’s boots his father dressed him in while on campaign with the legions in Germany. He became emperor at twenty-five and was enthusiastically welcomed by a people tired of Tiberius’s gloom.

Within months, however, Caligula was seriously ill, and when he recovered he was a different man. The chroniclers record that he demanded to be worshipped as a god, ordered his troops to invade Britain and then shamefully withdrew them at the last moment to collect seashells, and committed sexual offenses against senators’ wives at official banquets. Most famously — probably apocryphously — he made his favorite horse Incitatus a consul. Modern historians treat many of these stories with caution, but the picture they paint is of a man with an astonishing sense of his own divinity and a total contempt for the dignity of the Senate.

In January 41 CE, less than four years into his reign, Caligula was assassinated by officers of his own Praetorian Guard in a covered walkway of the imperial palace on the Palatine Hill. For a few hours the empire had no emperor, and the Senate seriously debated restoring the Republic. It was the Praetorian Guard — and not the Senate — that solved the succession problem by proclaiming Claudius, the stuttering, scholarly brother of Germanicus, as the new emperor. The discovery that the army, not the Senate, now chose the emperor was the central political fact of the rest of Roman history.

Claudius: The Unexpected Emperor (41 – 54 CE)

Claudius (born Tiberius Claudius Drusus, 10 BCE – 54 CE) was the least likely of the Julio-Claudians. He had a slight physical disability — probably cerebral palsy — and had been kept out of public life by his family for decades. He devoted himself to scholarship, writing twenty volumes of Etruscan history, eight of Carthaginian history, and a history of Rome that has not survived.

Once emperor, Claudius proved to be a remarkably efficient administrator. He extended Roman citizenship to the inhabitants of Gaul, expanded the imperial bureaucracy, and built the great harbor at Portus near Ostia to feed the capital. In 43 CE he launched the invasion of Roman Britain, which became the empire’s most notoriously unconquerable province. He was less successful in his marriages. His wife Messalina was executed in 48 CE for conspiring against him, and he then married his niece Agrippina the Younger, who dominated him completely. Agrippina persuaded him to adopt her son Lucius Domitius Ahenobarbus, the future Nero, over his own biological son Britannicus.

Claudius died on 13 October 54 CE, probably poisoned by a dish of mushrooms served at a dinner prepared by Agrippina’s taster. He was sixty-three and had ruled almost as long as Tiberius.

Nero: The Last of the Dynasty (54 – 68 CE)

Nero (born Lucius Domitius Ahenobarbus, 37 – 68 CE) was sixteen years old when he became emperor, and for the first five years of his reign the government was run by his mother Agrippina and by his tutor, the philosopher Seneca. His early reign was, by the standards of a teenage ruler, exemplary. But after Agrippina tried to dominate him and after the death of his wife Claudia Octavia, whom he divorced in order to marry his mistress Poppaea Sabina, Nero’s behavior grew steadily worse.

In 64 CE a great fire destroyed much of Rome. Whether Nero himself set the fire is disputed, but he certainly used the cleared land to build an enormous new palace, the Domus Aurea, and he blamed the Christians for the disaster, inaugurating the first imperial persecution. He killed his mother in 59 CE after a famous series of plots and counterplots. He kicked his pregnant wife Poppaea to death in 65 CE, married a young freedman named Sporus in a public ceremony complete with bridal veil and dowry, and dreamed of performing on stage as a singer and actor. The Greek east, where such performances were respected, loved him; the Roman aristocracy, where they were despised, did not.

In 68 CE the legions of Gaul and Spain revolted, and the praetorian prefect himself abandoned the emperor. Nero fled the palace and hid in the suburban villa of his freedman Phaon. On 9 June 68 CE, with soldiers hammering at the door, he pushed a dagger into his own throat. The last words he spoke, according to Suetonius, were “Qualis artifex pereo” — “What an artist dies with me.” He was thirty.

The Praetorian Guard and the Year of Four Emperors

Nero’s death left a power vacuum. The legions of the Rhine had already raised their commander Galba as emperor, and over the next eighteen months four men in succession claimed the throne: Galba, Otho, Vitellius, and finally Vespasian. The Year of the Four Emperors, 69 CE, was the first and most dangerous crisis of the empire. It was the legions on the frontiers, not the guards in Rome, who now decided who would rule.

Vespasian, an unflappable general who had been besieging Jerusalem when the war broke out, eventually emerged victorious. He founded a new dynasty, the Flavians, and began the construction of the Colosseum, the great amphitheater that still defines the heart of Rome. For the story of his dynasty, see the Flavian Dynasty.

The most important legacy of the Julio-Claudian years was not the dynasty’s violent end, however, but a quieter revolution. Under Augustus the emperor had been a civilian, ruling through the Senate. Under Caligula the Praetorian Guard had discovered that it could make emperors. Under Nero the army on the frontiers had discovered that it could unmake them. The lesson of the dynasty was that the Roman Empire now rested on the loyalty of its soldiers, and the dynasty that followed would be the dynasty to make that fact work.