Roman Empire: A Visual History

The Roman Empire is the imperial phase of a state that had already conquered the Mediterranean as a republic. Augustus ended a century of civil wars in 27 BC by keeping the forms of the Republic while holding all real power himself. For two hundred years the empire enjoyed relative peace and reached its greatest extent under Trajan in AD 117. Crisis in the third century, recovery under Diocletian and Constantine, the rise of Christianity and mounting pressure on the frontiers led to a permanent split in 395; the western half collapsed in 476, while the eastern half survived as the Byzantine Empire until 1453.

When it existed: the era ribbon

The bold bar is Roman Empire. The lighter bars are empires and wars from the same era and the same part of the world. Click any bar to jump to its page.

Territory of the Roman Empire

Approximate area under Roman rule; the figure after 395 counts both eastern and western halves.

Timeline of the Roman Empire

1. 44 BC
   Caesar assassinatedThe Ides of March; civil war follows.
2. 31 BC
   Battle of ActiumOctavian defeats Antony and Cleopatra.
3. 27 BC
   AugustusOctavian becomes Augustus; the empire begins.
4. 9
   Teutoburg ForestThree legions destroyed in Germany; the Rhine becomes the frontier.
5. 43
   Invasion of BritainClaudius adds a new province.
6. 64
   Great Fire of RomeNero blames the Christians.
7. 79
   Vesuvius eruptsPompeii and Herculaneum buried.
8. 117
   Greatest extentTrajan holds Dacia, Armenia and Mesopotamia.
9. 122
   Hadrian's Wall begunThe northern frontier of Britain fixed.
10. 212
    Citizenship for allCaracalla grants citizenship to all free inhabitants.
11. 235-284
    Crisis of the Third CenturyCivil war, plague, invasion and inflation.
12. 313
    Edict of MilanConstantine legalises Christianity.
13. 330
    Constantinople foundedThe empire's new eastern capital.
14. 378
    Battle of AdrianopleGoths kill the emperor Valens.
15. 395
    Permanent divisionEast and West under separate emperors.
16. 410
    Sack of RomeAlaric's Visigoths take the city.
17. 476
    Fall of the WestRomulus Augustulus deposed by Odoacer.

From Republic to Principate

Rome had ruled an empire long before it had an emperor. By the time Julius Caesar crossed the Rubicon in 49 BC, the Republic already held Spain, Gaul, Greece, Anatolia, Syria and North Africa. Caesar's assassination in 44 BC set off another round of civil war, won by his adopted heir Octavian at Actium in 31 BC.

Octavian was cleverer than Caesar. He restored the Senate's dignity, refused the title of king, and accepted the name Augustus in 27 BC while quietly gathering command of the armies, control of the richest provinces and a veto over everything. He called himself princeps, first citizen; historians call his system the Principate. It lasted, with adjustments, for nearly three hundred years.

Pax Romana and the peak

The first and second centuries were the empire's golden age. Roads, aqueducts, law and a common currency knitted together some 60 million people. Britain was conquered from AD 43, Dacia (Romania) by Trajan in 106, and Trajan briefly held Mesopotamia in 116-117, the empire's high water mark. Hadrian pulled back and built walls; Marcus Aurelius wrote philosophy while fighting on the Danube.

Not everything was calm. Nero's reign ended in revolt and the Year of the Four Emperors (69), the Jewish revolts were crushed with great violence, and Vesuvius buried Pompeii in 79. But the machinery of provincial government kept working almost regardless of who wore the purple.

The third century crisis and recovery

Between 235 and 284 the empire nearly disintegrated. More than twenty emperors came and went, most murdered; the currency was debased to almost nothing; plague swept the provinces; Persia captured the emperor Valerian in 260; and breakaway states formed in Gaul and Palmyra. Aurelian reunited the empire in 274, and Diocletian (284-305) rebuilt it with a larger army, heavier taxes and a system of four co-rulers, the Tetrarchy.

Constantine won the ensuing civil wars, legalised Christianity in 313, and in 330 founded a new capital at Constantinople. By 380 Christianity was the state religion. The empire that emerged from these reforms was more bureaucratic, more militarised and increasingly two empires in practice.

The fall of the West

In 376 Gothic refugees fleeing the Huns were admitted across the Danube, mistreated, and destroyed a Roman army at Adrianople in 378. Theodosius I was the last emperor to rule both halves; on his death in 395 the empire was permanently divided. The Visigoths sacked Rome in 410, the Vandals in 455, and Roman Britain, Spain and Africa slipped away to Germanic kingdoms.

In 476 the Germanic commander Odoacer deposed the boy emperor Romulus Augustulus and sent the imperial regalia to Constantinople. Nobody at the time thought the world had ended; the eastern emperors continued to claim the West, and Justinian briefly retook Italy and Africa in the sixth century. But 476 remains the conventional end of the Western Roman Empire.

Related empires and wars

Chosen automatically by overlap in time and geography, plus a few hand picked connections.

Empires of the same era and region

• Western Roman Empire (395 to 476)
• Byzantine Empire (395 to 1453)
• Parthian Empire (247 BC to 224)
• Sasanian Empire (224 to 651)
• Hunnic Empire (370 to 469)
• Ptolemaic Kingdom (305 BC to 30 BC)

Wars of the same era and region

• Gallic Wars (58 BC to 50 BC)
• Roman conquest of Britain (43 to 84)
• Jewish-Roman wars (66 to 136)
• Roman-Germanic wars (113 BC to 476)
• Social War (91-87 BC) (91 BC to 87 BC)

10 surprising things about the Roman Empire

1. Rome never officially became a monarchy. Emperors were technically just citizens holding a bundle of republican powers, which is why the Senate met for another 500 years.
2. The empire's peak lasted about a year. Trajan's Mesopotamian conquests of 116-117 were abandoned by Hadrian almost immediately.
3. In AD 212 Caracalla made every free person in the empire a Roman citizen, partly, historians suspect, to widen the tax base.
4. The Colosseum could be flooded for mock naval battles in its early years, before the basements were built.
5. Roman concrete has outlasted modern concrete partly because volcanic ash and seawater made it self-healing, a chemistry only fully understood in the twenty-first century.
6. The emperor Elagabalus (r. 218-222) reportedly staged a banquet in which guests were smothered under a shower of rose petals dropped from the ceiling.
7. Emperors were assassinated so often in the third century that Gordian I and Gordian II ruled for about three weeks between them.
8. The 'Roman salute' with the outstretched arm has no ancient evidence behind it; it comes from an eighteenth-century painting and later films.
9. Rome's population fell from perhaps a million in the second century to a few tens of thousands by the sixth; sheep grazed in the Forum for centuries.
10. The last emperor of the West, Romulus Augustulus, was named after both Rome's legendary founder and its first emperor, and lasted about ten months.

Sources

• Roman Empire Encyclopaedia Britannica
• Roman Empire Wikipedia
• Fall of the Western Roman Empire Wikipedia
• Roman Empire World History Encyclopedia
• Mary Beard, SPQR: A History of Ancient Rome (2015) Profile Books
• Peter Heather, The Fall of the Roman Empire (2005) Oxford University Press

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