THE WORLD ATLAS

Empire · 27 BCE – 476 CE · Europe

Roman Empire

Also known as Rome (Diocletianus), Rome (Maximian), Rome (Constantinus), Rome (Galerius), Western Roman Empire

After a century of civil war, Octavian, Julius Caesar's heir, became Rome's first emperor as Augustus in 27 BCE, keeping the forms of the Republic while holding real power. The two centuries that followed, the Pax Romana, brought peace and prosperity to an empire that ringed the Mediterranean, linked by roads, a professional army, Roman law and Latin and Greek culture; in 212 almost all free inhabitants became citizens.

The 3rd century brought invasions, plague and a rapid turnover of emperors. Diocletian reorganised the empire under several co-rulers, and Constantine embraced Christianity and founded Constantinople. After 395 the empire was permanently divided into eastern and western halves. The West, weakened by Germanic migrations and lost revenue, ended when Odoacer deposed Romulus Augustulus in 476.

Follow its story on the map

The Colosseum in Rome, begun under Vespasian c. 70–72 CE and opened in 80 CE
The Colosseum in Rome, begun under Vespasian c. 70–72 CE and opened in 80 CE Diliff · CC BY-SA 2.5
Years
27 BCE – 476 CE
Capital
Rome; from 330 also Constantinople, and later Milan and Ravenna in the West
Greatest extent
117, about 5.00 million km²
Region
Europe

Under Trajan, from Britain to Mesopotamia; c. 5.0M km² c. 117 (Taagepera 1979; Turchin, Adams & Hall 2006)

Legacy

Rome's law, Latin language, roads, cities and adoption of Christianity form the backbone of European civilisation.

Timeline of Roman Empire

  1. Monarchy overthrown; the Republic, led by two annual consuls, begins

    According to Roman tradition, Rome was ruled by kings until the last of them, Tarquinius Superbus, was driven out after his son Sextus raped the noblewoman Lucretia. The rebels replaced the monarchy with a republic in which two consuls, elected every year, held the highest power, so that no single man could rule for life. The traditional date of 509 BCE comes from a chronology assembled centuries later, and many modern scholars treat the story as largely legendary. Whatever the details, the new Republic was still only a small city-state on the Tiber, one power among many in central Italy.

  2. Rome defeats the Latin League and dominates Latium

    In the 4th century BCE Rome led a league of neighbouring Latin cities, but the Latins resented its growing dominance and went to war in 340 BCE. After defeats at Trifanum and finally at Pedum in 338 BCE, the Latin League was dissolved. Rome did not simply crush the Latins: their territory was brought into the Roman sphere, and the cities received partial rights or varying levels of Roman citizenship that tied them to Rome. The settlement made Rome master of Latium and gave it a model for ruling conquered Italians that fuelled its expansion across the peninsula.

  3. Tarentum surrenders: Rome controls peninsular Italy

    The Greek city of Tarentum in southern Italy feared Roman expansion, and in 281 BCE it invited King Pyrrhus of Epirus to fight on its side. Pyrrhus beat the Romans at Heraclea and Asculum, but at such cost that a 'Pyrrhic victory' became a byword, and after fighting at Beneventum in 275 BCE he withdrew to Greece. In 272 BCE Tarentum fell to Rome, and its Epirote garrison was allowed to sail home. Rome now controlled peninsular Italy, and its victory over a Hellenistic king showed that it had become a major Mediterranean power.

  4. First Punic War won; Sicily becomes the first province

    Rome's first war with Carthage, the great sea power of North Africa, began in 264 BCE over Messana in Sicily and lasted 23 years, the greatest naval war of antiquity. After immense losses on both sides, the Romans slowly occupied most of the island. In 241 BCE a Roman fleet destroyed a Carthaginian relief force off the Aegates Islands, leaving Carthage's army in Sicily cut off and forcing it to seek peace. Carthage paid large reparations and gave up Sicily, which became Rome's first province outside Italy and the start of an overseas empire.

  5. Rome defeats Carthage at Zama, winning the Second Punic War

    In the Second Punic War Hannibal invaded Italy, but Rome fought back in Spain, where Scipio cleared out the Carthaginians in five years, and then carried the war to Africa. Carthage recalled Hannibal from Italy to defend the homeland. At Zama in 202 BCE, in what is now Tunisia, Scipio's army of about 40,000, stronger in cavalry, defeated Hannibal's larger force and its 80 war elephants. The peace stripped Carthage of all its lands outside Africa and some within it. Spain passed to Rome, and Carthage was left a subordinate power, no longer a rival for the western Mediterranean.

  6. Carthage destroyed; Achaean League crushed at Corinth

    By the mid-2nd century BCE Rome dominated the Mediterranean but still crushed any sign of resistance. In the Third Punic War (149–146 BCE) a Roman army besieged Carthage; in 146 the city was stormed and systematically destroyed, and some 50,000 survivors were sold into slavery. The same year, in Greece, the consul Lucius Mummius defeated the Achaean League at Corinth, burned the city and enslaved its women and children. Carthage's lands became the Roman province of Africa, and the rest of Greece fell under Roman control beside the new province of Macedonia.

  7. Caesar's Gallic Wars begin with the campaign against the Helvetii

    Julius Caesar, an ambitious general deep in debt, wanted military glory to boost his political career. In 58 BCE the migration of the Helvetii from what is now Switzerland gave him a reason to intervene in Gaul, and by 57 he had resolved to conquer all of it. Over the following years he fought Gallic, Germanic and British peoples, crossing twice to Britain, and in 52 BCE he crushed the great revolt led by Vercingetorix at the siege of Alesia. Rome's rule now extended over the whole of Gaul (present-day France, Belgium and Switzerland), pushing its frontier to the Rhine.

  8. Octavian defeats Antony and Cleopatra at Actium; Egypt annexed in 30

    After Julius Caesar's murder, his heir Octavian and the general Mark Antony shared power, but Antony allied himself with Cleopatra VII of Egypt and the two men became rivals. On 2 September 31 BCE Octavian's fleet, commanded by Marcus Agrippa, defeated Antony and Cleopatra off Actium in western Greece. Octavian pursued them to Alexandria, which fell on 1 August 30 BCE, and both took their own lives. Egypt, the last surviving kingdom of Alexander's successors, was annexed, and Octavian, given the name Augustus in 27 BCE, ruled as the first emperor: the Republic had given way to one-man rule.

  9. Germanic coalition destroys three Roman legions in the Teutoburg Forest

    Under Augustus, Rome tried to bring Germania, the lands beyond the Rhine, under its control. In 9 CE the governor Publius Quinctilius Varus led three legions and their auxiliaries into the Teutoburg Forest, where they were ambushed and destroyed by a Germanic alliance led by Arminius, a chieftain who had served as an officer in Varus's own auxiliary troops. Later campaigns under Tiberius and Germanicus took revenge but did not reconquer the region. The disaster ended Augustus's expansion in the north, and the Rhine became the lasting border between the Empire and free Germania.

  10. Trajan dies with the empire at its greatest extent

    Trajan, emperor from 98 to 117 CE, was a soldier-emperor who led one of Rome's greatest military expansions. He conquered Dacia north of the Danube and annexed Nabataea in Arabia, then attacked the Parthian Empire and made Armenia, Mesopotamia and Assyria into provinces. In August 117 he fell ill while sailing back to Rome and died at Selinus in Asia Minor, with the empire at its largest, about 5 million km². His successor Hadrian quickly abandoned Mesopotamia as too costly and distant to defend, so the eastern frontier pulled back again.

  11. Valerian captured by Persia; the Gallic Empire breaks away

    The third century brought civil wars, invasions and economic trouble. Emperor Valerian left the West to his son Gallienus and marched east against the Sasanian Persians, but after the Battle of Edessa in 260 CE he was captured by Shapur I, the first Roman emperor ever taken prisoner in battle. With much of the eastern army lost, Postumus, the commander on the Rhine, declared himself emperor and founded the breakaway Gallic Empire, which at its height held Gaul, Britain, Hispania and the Germanies. By 268 the empire had split into three states, until Aurelian reunited it by 274.

  12. Theodosius I dies; the empire is split between Arcadius and Honorius

    Theodosius I, emperor from 379, won two civil wars and became the last emperor to rule the whole Roman world. He had already made his two young sons co-emperors, and when he died in January 395 they succeeded him jointly: Arcadius in the East, ruling from Constantinople, and Honorius, aged ten, in the West. The split followed a long practice of shared rule, but this time it proved permanent. From now on the map shows two separate empires: the Eastern half would survive for another thousand years, while the West entered its final decline.

  13. Alaric's Visigoths sack Rome; Britain effectively abandoned

    After years of failed bargaining with the Western court at Ravenna over land and rank for his people, the Visigothic king Alaric besieged Rome and starved it into submission. On 24 August 410 his men entered the city and plundered it for three days, the first time in almost 800 years that Rome had fallen to a foreign enemy. The same year Honorius refused Britain's appeal for military help: the last mobile troops had left the island with the usurper Constantine III in 407, and the Romano-British had expelled Roman officials. Britain slipped out of the Empire for good.

  14. Vandals take Carthage and the rich African provinces

    The Vandals, a Germanic people, crossed from Spain to North Africa in 429 under their king Gaiseric (Geiseric) and conquered much of the coast of today's Algeria and Tunisia. In 439 Gaiseric broke a treaty with Rome and took Carthage, apparently without a fight while many of its people were at the races. North Africa had been a major source of tax revenue and of the grain that fed Rome, so its loss crippled the Western Empire. The Vandals went on to seize Sicily, Sardinia and Corsica, and sacked Rome itself in 455.

  15. Odoacer deposes Romulus Augustulus at Ravenna: end of the Western Empire

    By the 470s the Western emperors were puppets of powerful generals and controlled little beyond Italy. In 475 the general Orestes drove out Julius Nepos and put his young son Romulus on the throne. When Orestes refused to give Italian land to the barbarian troops in Roman service, they rallied behind their officer Odoacer, who killed Orestes and took Ravenna on 4 September 476, deposing Romulus. Odoacer named no new emperor, ruled as king of Italy, and the imperial insignia were sent to the Eastern emperor Zeno: the Western Roman Empire was gone from the map.

Periods and reigns

Rulers

Realms on the map

Chapters

Sources