Roman Empire: Timeline, Emperors, Government and Legacy, 27 BCE-1453
The Roman Empire from Augustus in 27 BCE to the fall of the West in 476 and of Constantinople in 1453: its phases, its size at its peak, how it was governed and defended, its religion and citizenship, and what it left behind.
Last updated September 2026
Contents16
- The Roman Empire at a glance
- From kingdom to republic to empire
- The phases of the Roman Empire
- The Roman Empire at its height
- Governing the empire
- The army and the frontiers
- Citizenship and law
- Religion: from many gods to Christianity
- Language and culture
- Daily life in the Roman Empire
- Roman cities across the empire
- Roads and trade
- How long did the Roman Empire last
- The end of the Roman Empire
- The legacy of the Roman Empire
- Verdict: the Roman Empire in brief
The Roman Empire was one of the largest and longest-lasting states in history. It grew out of the Roman Republic and had emperors from 27 BCE. At its height, in the 100s CE, it ruled the whole Mediterranean world.
Its Western half fell in the 400s. Its Eastern half lasted until 1453. This page gives the timeline and the main phases. It shows how Rome ruled and defended the empire, how it held together, and what it left behind.
TL;DR: The Roman Empire began in 27 BCE with Augustus. It reached its greatest size under Trajan in 117 CE. It nearly fell apart in the 200s. It took up Christianity in the 300s and split into two halves in 395. The West ended in 476-480. The East, ruled from Constantinople, fell to the Ottomans in 1453. Its law, its languages and the religion it spread still shape the world.
The Roman Empire at a glance
| Field | Record | Status |
|---|---|---|
| Began | 27 BCE, when Octavian became Augustus | Reviewed |
| Greatest extent | 117 CE, under Trajan | Reviewed |
| Capitals | Rome; later also Milan, Ravenna and Constantinople (dedicated 330) | Reviewed |
| Languages | Latin and Greek | Reviewed |
| Division into East and West | 395 | Reviewed |
| End of the West | 476 or 480 | Disputed |
| End of the East | 1453 | Reviewed |
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From kingdom to republic to empire
By tradition, kings ruled Rome from its founding in 753 BCE until about 509 BCE. Then the last king was driven out. The Roman Republic followed.
Elected officials ran it, above all two consuls each year, along with the Senate. Under the republic Rome conquered Italy and beat Carthage. It took control of Greece, Spain and much of the eastern Mediterranean.
Civil wars in the first century BCE destroyed the republic. Julius Caesar became dictator. Senators killed him in 44 BCE.
His heir Octavian beat his rivals. In 27 BCE he was given the name Augustus. That year is usually taken as the start of the Roman Empire. The who is the first Roman emperor page tells the story.
The phases of the Roman Empire
| Phase | Years | Main features |
|---|---|---|
| Principate | 27 BCE-235 CE | Emperor as "first citizen"; the Pax Romana; greatest expansion |
| Crisis of the Third Century | 235-284 | Civil wars, invasions, plague, debased coinage |
| Dominate | 284-395 | Diocletian's and Constantine's reforms; Christianity adopted; new capital |
| Divided empire | 395-476/480 | Separate Western and Eastern courts; the West collapses |
| Eastern Roman Empire | 476/480-1453 | Rule from Constantinople; later called Byzantine |
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For the emperors of each phase, see emperors of Rome. For the families that held the throne, see Roman dynasty.
The Roman Empire at its height
Under Trajan, in 117 CE, the empire reached its largest size. It stretched from northern Britain to the Persian Gulf. It ran from the Rhine and Danube to the Sahara. Trajan added Dacia, north of the Danube.
For a short time he also held Armenia and Mesopotamia. His heir, Hadrian, gave up the lands in Mesopotamia. He made the frontiers stronger instead. That included the wall across northern Britain, begun in 122.
| Region | Examples of provinces |
|---|---|
| Western Europe | Britannia, the Gallic provinces, Hispania, the Germanies |
| Central Europe and the Balkans | Raetia, Noricum, Pannonia, Dacia, Moesia, Thrace, Macedonia |
| Italy and the islands | Italy itself, Sicily, Sardinia, Corsica |
| Anatolia and the Near East | Asia, Galatia, Cappadocia, Syria, Judaea, Arabia |
| Africa | Egypt, Cyrenaica, Africa Proconsularis, Numidia, the Mauretanias |
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How that size compares with other empires is set out on the largest empire in history page.
Governing the empire
The emperor stood at the top. He controlled the army, the treasury and foreign policy. The Senate kept great prestige and some formal powers.
Rome split the empire into provinces. A governor with a small staff ran each one. Under Augustus, the emperor's own deputies ran provinces that needed legions. Senators ran the peaceful ones.
Much of daily rule was local. Hundreds of cities ran their own affairs through local councils. They collected taxes for Rome.
They built temples and baths. Many built theatres too. This network of self-ruling cities held the empire together. Roads and a shared law linked them.
The army and the frontiers
The Roman army was a full-time, paid force. Augustus set it at about 28 legions of citizen soldiers. A similar number of non-citizen troops, called auxiliaries, backed them up.
Soldiers served for about 20-25 years. When they left, they got land or money. Auxiliaries could earn Roman citizenship for their service.
Most troops served along the frontiers, known as the limes. In places, walls and forts marked them, linked by roads. In the later empire the army was split into frontier troops and field armies that could move. It also relied more on soldiers from outside the empire.
Citizenship and law
Roman citizenship brought legal rights and status. At first only people from Rome and Italy held it. But it spread step by step to provincial elites and soldiers. In 212 CE Emperor Caracalla gave citizenship to almost all free people in the empire. His decree is known as the Constitutio Antoniniana.
Roman law was one of the empire's great achievements. Legal experts built it up over centuries. In the 500s, Justinian I gathered it into one code in the East. That code became the basis of legal systems across much of Europe.
Religion: from many gods to Christianity
The Romans worshipped many gods. They accepted foreign cults, as long as those did not threaten public order. An imperial cult honoured the emperors. After death, the Senate declared many of them gods.
Christianity spread from the first century. It faced times of persecution, such as under Decius in 250 and under Diocletian from 303. In 313 Constantine and Licinius agreed to tolerate it.
That policy is known as the Edict of Milan. Theodosius I made Nicene Christianity the state religion in 380. He banned pagan sacrifice in the 390s.
Language and culture
Latin spread across the Western provinces. It became the parent of the Romance languages: Italian, French, Spanish, Portuguese and Romanian. In the East, Greek stayed the main language.
Educated Romans everywhere learned it. The empire produced writers such as Virgil, Ovid, Livy, Tacitus and Seneca. It also took in Greek art and thought. Greek science came too.
Roman builders left roads and bridges. They left aqueducts and harbours too. They left domed buildings such as the Pantheon. The Colosseum opened in 80 CE. It held tens of thousands of people for gladiator games.
Daily life in the Roman Empire
Most people in the empire lived in the countryside and worked the land. But cities set the tone of Roman life. A typical town had a forum for business and politics.
It had temples, public baths and often a theatre or arena. Water arrived by aqueduct. It ran through lead pipes to fountains and baths.
Slavery was widespread. Enslaved people worked in homes and fields, in mines and in workshops. Many were freed and became citizens. The father headed the family. He had wide legal power over his household.
Roman cities across the empire
Many of Europe's major cities began as Roman towns or grew under Roman rule. They include London (Londinium), Paris (Lutetia) and Cologne (Colonia Agrippina). They also include Vienna (Vindobona) and Barcelona (Barcino). In the east, older cities such as Alexandria, Antioch and Ephesus did well under Rome. They stayed among the largest cities of the empire.
Roads and trade
Roman roads linked the provinces to one another and to Rome. The army built them first, but traders and officials used them too. By sea, grain ships brought food from Egypt and North Africa to feed Rome.
Trade goods moved across the whole Mediterranean. Shared coins, shared laws and a long peace helped trade. In the first two centuries CE, the empire was one of the largest trading areas of the ancient world.
How long did the Roman Empire last
Length of the Roman Empire
How long the Roman Empire lasted.
Status: Disputed The answer depends on whether the Eastern empire is counted.
Note: From Augustus in 27 BCE to the end of the Western empire in 476 is just over 500 years. The Eastern Roman Empire called itself Roman until the end. If it counts, the empire lasted until the Ottomans took Constantinople on 29 May 1453. That is nearly 1,500 years. Add the kingdom and the republic, and Roman history goes back to the city's founding, by tradition in 753 BCE.
Sources: Britannica, "Ancient Rome"; The Metropolitan Museum of Art, "The Roman Empire (27 B.C.-393 A.D.)".
The end of the Roman Empire
The Western empire weakened in the 400s. It suffered invasions and lost its richest provinces. In 476 the general Odoacer removed Romulus Augustulus and did not replace him. Julius Nepos, the last Western emperor the East recognised, died in 480. The decline of the Roman Empire page discusses the causes.
The Eastern empire carried on. It won back parts of the West under Justinian I and survived the Arab conquests. It lasted until the Ottoman Turks took Constantinople in 1453. The Eastern Roman Empire hub tells that story.
The legacy of the Roman Empire
The Roman Empire left a deep mark on the world.
- Law: Roman law underlies the civil-law systems of continental Europe and Latin America.
- Language: the Romance languages grew from Latin, and English borrowed thousands of Latin words.
- Religion: the empire spread Christianity, and the Catholic and Orthodox churches both grew from its structures.
- Government: words such as senate and republic, emperor and province, come from Rome.
- Calendar: the Julian calendar, introduced by Julius Caesar in 46 BCE, was the basis of the calendar used today.
Later rulers claimed Rome's heritage. They ranged from the Holy Roman emperors to the Russian tsars, whose title comes from "Caesar".
To read more, try our guide to the best Roman history books. It picks seven. Together they cover Rome from the Republic to 1453.
Verdict: the Roman Empire in brief
The Roman Empire began in 27 BCE with Augustus. It reached its largest size under Trajan in 117 CE and split in 395. Its Western half ended in 476-480.
Its Eastern half lasted until 1453. So it lasted either about five centuries or nearly fifteen, depending on whether the East counts. Its law, its languages and its religion outlived it. For the eastern empire that kept the name to 1453, see the Byzantine Empire page.
Sources checked for this page
- Britannica, "Ancient Rome"
- Britannica, "Ancient Rome: The Later Roman Empire"
- The Metropolitan Museum of Art, "The Roman Empire (27 B.C.-393 A.D.)"
- World History Encyclopedia, "Roman Empire"
- UNRV, "The Roman Empire"
- Britannica, "Constantine I"
Questions people also ask
When did the Roman Empire start?
In 27 BCE, when the Senate gave Octavian the name Augustus. Rome had been expanding as a republic for centuries before that, but 27 BCE marks the start of rule by emperors.
When was the Roman Empire at its largest?
Under Trajan, in 117 CE, when it stretched from Britain to Mesopotamia and from the Rhine and Danube to Egypt and North Africa.
How long did the Roman Empire last?
About 500 years if it ends with the Western empire in 476, or nearly 1,500 years if the Eastern Roman Empire, which fell in 1453, is included.
What language did the Romans speak?
Latin was the language of Rome, the army and the law, and it dominated the western provinces. Greek was the common language of the eastern provinces and of educated people across the empire.
What was the capital of the Roman Empire?
Rome, for most of its history. In the late empire emperors also ruled from cities such as Milan, Trier and Ravenna, and from 330 Constantinople served as the capital in the east.
Who was the last emperor of the Roman Empire?
In the West, Romulus Augustulus was deposed in 476, although Julius Nepos kept the title until 480. In the East, Constantine XI died when Constantinople fell in 1453.