History of the Roman Empire

• 1. Introduction

  ›

  The History of the Roman Empire begins with a single battle on the 2nd of September, 31 BC, when Octavian's fleet met Mark Antony and Queen Cleopatra VII of Egypt off the coast of Greece at Actium. Antony lost. Cleopatra lost. And in the wreckage of that afternoon, a republic that had governed Rome for five centuries quietly ceased to be the thing it claimed to be. What followed was not a revolution anyone announced. It was a long, careful fiction: that the old republic still existed, that its institutions still held power, and that the man now running everything was merely its first citizen. That fiction would last for centuries, shape the laws of nations that would not be born for another thousand years, and finally expire not in Rome at all but in a city on the Bosphorus in 1453. What was the Roman Empire, really? How did it hold together a world stretching from Britain to the Persian Gulf? And why, in the end, did it fall? The answers begin not with a proclamation, but with a deal struck between a young general and a very old Senate in 27 BC.

• 2. Augustus and the New Order

  ›

  In 27 BC, the Roman Senate gave Octavian two titles: Augustus, meaning venerated, and Princeps, meaning foremost. Neither word meant king. That was the point. The word rex, meaning king, carried a weight of ancient hatred in Rome, and Augustus spent the rest of his life avoiding it. What he built instead was a novel position assembled from the constitutional powers of several existing offices at once. By 23 BC he had renounced his consulship but kept consular authority. He held the power of a tribune without the title, which let him convene the Senate, veto any law, and preside over elections. He also exercised the powers of a censor, controlling the membership of the Senate itself, though he was never elected to that office either. No single Republican office had ever combined all of these, and there was no precedent for it. The Senate, for its part, reclassified the frontier provinces as imperial provinces under Augustus's direct command, while the peaceful interior provinces remained senatorial. Taxes from the imperial provinces flowed into the fiscus, a fund answerable only to Augustus. This gave him control over the loyalty of the legions through their pay. He reduced those legions from fifty to twenty-eight, carefully merging units of doubtful loyalty. Three of his nine special cohorts, the Praetorian Guard, were kept in Rome itself. The one catastrophe Augustus could not contain came in AD 9 in the forests of Germania, where three full legions under Publius Quinctilius Varus were ambushed and destroyed by Germanic tribes led by Arminius at the Battle of the Teutoburg Forest. After that, the Rhine and Danube became the permanent northern borders of the empire. Augustus died in AD 14 at the age of seventy-five, having ruled for forty years, and the title he had inherited from Julius Caesar, Imperator, passed to his stepson Tiberius. That word imperator is the root of the English word emperor.

• 3. Dynasty, Madness, and Fire

  ›

  Tiberius inherited an empire in good financial health but governed it increasingly through paranoia. He retired to his villa on the island of Capri in 26, leaving Rome under Lucius Aelius Sejanus, the commander of the Praetorian Guard. Sejanus consolidated power, became co-consul with Tiberius in 31, and married the emperor's niece Livilla before Tiberius turned his own methods against him. Sejanus was executed that same year, and the treason trials continued until Tiberius died in 37. His successor Caligula, twenty-four years old at accession, began well: he ended the persecutions and destroyed his predecessor's records. What emerged from a period of illness in late 37 was, in the accounts of Suetonius, a different man entirely. According to Suetonius in Lives of the Twelve Caesars, Caligula once planned to appoint his favourite horse Incitatus to the Senate, ordered his soldiers to collect seashells on the northern coast of France as spoils of a campaign against the sea god Neptune, and was believed to have maintained incestuous relationships with all three of his sisters: Julia Livilla, Drusilla, and Agrippina the Younger. He ordered a statue of himself erected in Herod's Temple at Jerusalem, a plan abandoned only at the urging of his friend King Agrippa I. He was assassinated in 41 by the guard commander Cassius Chaerea. For two days after his death the Senate debated whether to restore the Republic. Instead, the Praetorian Guard proclaimed his uncle Claudius emperor. Claudius was considered a fool by his family but proved a capable administrator. He ordered the construction of a winter port at Ostia Antica, oversaw the resumption of the Roman conquest of Britannia that Julius Caesar had begun in the 50s BC, and incorporated eastern provinces into the empire. His wife Messalina's infidelities led him to have her executed; he then married his niece Agrippina the Younger, who may have poisoned him in 54. His death cleared the way for Agrippina's seventeen-year-old son, Nero. Nero built theatres, promoted athletic games, fought a successful war against Parthia, and suppressed Boudica's revolt in Britannia between 60 and 61. He also had his mother stabbed to death after multiple failed attempts on her life. Following the Great Fire of Rome in 64, Nero constructed the Domus Aurea, a palace whose gilded, jewel-encrusted ceilings required entirely new methods of construction, on the burned ground. He blamed Christians for the fire and the misery of his reign. When a military coup drove him into hiding in 68, the Senate sentenced him to death. He reportedly committed suicide that same year. Cassius Dio records his final words: "Jupiter, what an artist perishes in me."

• 4. Stability and Its Limits

  ›

  Between June 68 and December 69, Rome cycled through Galba, Otho, and Vitellius before Vespasian emerged as emperor, founding the Flavian dynasty. The chaos of that year proved something that would haunt the empire for centuries: military power alone could make an emperor. Provincial legions had developed stronger loyalty to their own commanders than to the man in Rome. On the 20th of December 69, Vespasian's supporters occupied the city, Vitellius was murdered by his own troops, and the sixty-year-old Vespasian was confirmed by the Senate the following day. Vespasian repaired Rome's finances through new and expanded taxation, used his power as censor to rebuild a Senate that Nero had reduced to roughly two hundred members back up to one thousand, and granted Latin Rights to more than three hundred towns and cities across Hispania. He also commissioned the Amphitheatrum Flavium, which later generations would call the Colosseum. His son Titus held the opening ceremonies in the still-unfinished building in the year 80, staging a show featuring one hundred gladiators that lasted one hundred days. Titus died in 81 at the age of forty-one. His brother Domitian then ruled until 96, keeping the treasury well-stocked but provoking such fear in his own household that his murder was orchestrated by his wife, the empress Domitia Longina, members of the Praetorian Guard, and a steward named Stephanus. His successor Nerva released political prisoners, banned treason prosecutions, and restored confiscated property, but the Praetorian Guard besieged the Imperial Palace in October 97 and took Nerva hostage, forcing him to thank the mutineers publicly for their rebellion. Nerva's decision shortly after to adopt as his successor Trajan, a commander on the German frontier, set the pattern for the next century: emperors choosing successors by merit rather than blood.

• 5. The Five Good Emperors

  ›

  Trajan crossed the Danube personally in 101 to fight the Dacian king Decebalus at the Battle of Tapae. After defeating him and imposing peace terms, Trajan returned to Rome, took the honorific Dacicus, and watched as Decebalus broke the terms within a few years. A second invasion in 105 ended with the fall of the Dacian capital Sarmizegetusa Regia; Decebalus cornered by Roman cavalry chose suicide over capture. Trajan ordered one hundred and twenty-three days of celebration and constructed Trajan's Column in the Forum of Trajan to mark the victory. He then turned east: by 116 he had taken Babylon, Seleucia, and the Parthian capital Ctesiphon, and reached the Persian Gulf. He lamented publicly that he was too old to follow Alexander the Great further. During his reign the Roman Empire reached its greatest territorial extent. His successor Hadrian surrendered those Mesopotamian conquests as indefensible and turned to the empire's internal fabric, becoming the first emperor to extensively tour the provinces and funding local construction projects along the way. In Britain he ordered the construction of Hadrian's Wall. His army crushed the Bar Kokhba revolt in Judea between 132 and 135. Antoninus Pius followed with a comparatively quiet reign; disturbances in Mauretania, Judea, and among the Brigantes in Britain prompted the construction of the Antonine Wall between the Firth of Forth and the Firth of Clyde, though it was soon abandoned. Marcus Aurelius faced far graver pressures: Germanic raids across the Danube, a revitalised Parthian assault in the east, and a rebellion by the general Avidius Cassius in 175, who seized Egypt and Syria after hearing a false report of Marcus's death. Marcus restored order within three months, then wrote his Stoic philosophical work the Meditations in the final years of his life. The Greek historian Cassius Dio, a contemporary observer, later wrote that the accession of Marcus's son Commodus in 180 marked the descent from "a kingdom of gold to one of rust and iron." The historian Edward Gibbon took that same moment as the beginning of the Roman Empire's decline.

• 6. Crisis and Fragmentation

  ›

  In 212, the emperor Caracalla issued the Antonine Constitution, granting Roman citizenship to nearly all free inhabitants of the empire. It was the broadest single extension of citizenship in Roman history, yet Caracalla himself was murdered by the Praetorian Guard two years later, en route to a campaign against Parthia. The Severan dynasty he belonged to was, in the source's phrase, tumultuous: emperors routinely ended their reigns through murder or execution. When Severus Alexander was killed by his own troops in 235, the empire entered what historians call the Crisis of the Third Century, a fifty-year period of invasions, civil strife, economic disorder, and epidemic disease. In 251 the Plague of Cyprian, possibly smallpox, broke out across the empire, causing large-scale mortality that may have severely weakened the empire's capacity to defend its borders. By 258, the empire had fractured into three competing states: the Gallic Empire in the northwest, the Palmyrene Empire in the east, and the remnant Roman state in the middle. An invasion by a vast force of Goths was beaten back at the Battle of Naissus in 269, which proved to be the turning point. The emperor Aurelian, who had commanded the cavalry at Naissus, reunited the empire by late 274 after defeating the Vandals, Visigoths, Palmyrenes, Persians, and the remaining Gallic Empire in sequence. Whole cities that had flourished for centuries had been ruined by this point and could not be rebuilt. Even Rome itself, which had not needed city walls for centuries, surrounded itself with thick new fortifications. The structural problem Aurelian had not solved was the lack of any clear law of succession, which guaranteed that every death on the throne became an opportunity for civil war. That problem fell to Diocletian.

• 7. Division and New Faith

  ›

  Diocletian defeated his rival Carinus in July 285 and immediately set about restructuring the empire from its foundations. He appointed a co-emperor in 286 and on the 1st of March 293 formalised the Tetrarchy: two senior emperors, each called augustus, and two junior emperors, each called caesar, governing four regional quarters of the empire. He moved the imperial administrative centers away from Rome to Nicomedia, Mediolanum, Antioch, and Trier, cities closer to the frontiers where the real threats were. His tax reform from at least 297 onward standardised and generally increased imperial levies to fund the enlarged military and bureaucracy. He also launched the Diocletianic Persecution of Christians beginning in 303, described in the source as the empire's last, largest, and bloodiest official persecution of Christianity. On the 1st of May 305, Diocletian became the first Roman emperor to voluntarily abdicate, retiring to a palace on the Dalmatian coast where he tended to his vegetable garden. That palace would eventually become the core of the modern city of Split. The Tetrarchy collapsed almost immediately after his abdication. Constantine, son of the western caesar Constantius Chlorus, was proclaimed augustus by his father's troops in Eboracum on the 25th of July 306, the very day Constantius died. By 324, after years of civil war, Constantine had defeated all rivals and unified the empire under sole rule. He founded a new capital, Constantinople. He also became the first emperor to convert to Christianity. The Edict of Milan in 313 had already legalised Christianity across the empire; by the time Theodosius I died in 395 after making Christianity the empire's official religion, the faith had traveled from persecution to state religion within a single century.

• 8. Two Endings

  ›

  The Western Roman Empire began to break apart in the early 5th century as the Germanic migrations of the Migration Period overwhelmed the empire's capacity to absorb newcomers and repel invaders at the same time. Most chronologies mark its end in 476, when Romulus Augustulus was forced to abdicate to the Germanic warlord Odoacer. The name was almost poetic in its irony: the last emperor in the west carried the name of Rome's legendary founder. The Eastern Empire, which its own inhabitants still called Roman and which later historians would call Byzantine, outlasted the west by nearly a thousand years. It had been reduced to Anatolia and the Balkans by the 7th century as Arab armies swept across Egypt, Syria, and much of its former eastern territory. Its final moment came on the 29th of May 1453, when Ottoman forces under Mehmed II breached the walls of Constantinople. The last emperor, Constantine XI, died in the fighting. The empire that had begun when Octavian accepted the title of Augustus in 27 BC had lasted, in one form or another, for fifteen centuries. The word Augustus itself had never stopped being used: every emperor from Octavian onward inherited it, and the eastern emperors carried it to the very end.