Ancient Rome: Rise, Empire, and Influence

Few civilizations have shaped the modern world as decisively as ancient Rome. The legal principles, the languages, the engineering standards, the calendar, the religion, and the very idea of a European civilization all trace back, in some way, to a small village on the Italian peninsula that grew, over thirteen centuries, into the largest empire of the ancient West.

This pillar walks through that long story: the founding myths, the Republic, the Empire, the great figures from Julius Caesar to Constantine, and the eventual decline. Along the way it links out to the deep dives on Roman Gladiators, Roman Engineering, the Colosseum, the Roman Forum, and the famously well-preserved city of Pompeii and Herculaneum.

The Geography of Roman Power

Rome is built on seven hills beside the Tiber River, about twenty miles inland from the Tyrrhenian Sea. From this unpromising position in central Italy, the Romans eventually ruled a territory that, at its height in the early second century CE, stretched from Hadrian’s Wall in northern Britain to the sands of Mesopotamia, and from the Rhine and the Danube to the Atlas Mountains and the Euphrates.

Three features gave Rome its edge:

Italy itself. A long, mountainous peninsula with a temperate climate, fertile plains, and excellent natural harbors.
The Mediterranean. The Romans called it Mare Nostrum — “Our Sea.” Control of the Mediterranean let Rome move grain, soldiers, money, and ideas cheaply and quickly.
A pragmatic political culture. The Romans were unusually willing to copy useful institutions from the peoples they conquered — the Greek gods, the Etruscan augury, the phalanx tactics they borrowed from the Greeks, the legal codes of the Hellenistic East.

A Brief Timeline

Roman history is conventionally divided into three major periods.

The Regal and Republican Periods (753 BCE – 27 BCE)

Traditional legend dates the founding of Rome to 753 BCE, when Romulus, son of Mars, killed his brother Remus and founded the city on the Palatine Hill. The first centuries of Rome were ruled by a line of kings, several of them Etruscan, until the last king, Tarquinius Superbus, was expelled around 509 BCE and a republic was declared.

The Roman Republic was governed by a complex constitution of elected magistrates (two consuls, praetors, aediles, quaestors), a senate drawn from the patrician and wealthy plebeian classes, and popular assemblies. For nearly four hundred years the Republic expanded across the Mediterranean, defeating the Punic Wars rival Carthage, absorbing Greece, conquering Gaul under Julius Caesar, and acquiring a vast overseas empire.

The Republic’s last century was consumed by a series of civil wars between rival generals — Marius and Sulla, Pompey and Caesar, Antony and Octavian. The decisive moment came on 15 March 44 BCE, when Caesar was assassinated in the Theatre of Pompey (see Ides of March). Within fifteen years his adopted son Octavian had defeated all rivals and, in 27 BCE, became Augustus, the first Roman emperor.

The High Empire (27 BCE – 180 CE)

The first two centuries of the empire — the Principat — were, in many ways, Rome’s golden age. The emperors Augustus, Tiberius, the Flavians (Vespasian, Titus, Domitian), the “Five Good Emperors” (Nerva, Trajan, Hadrian, Antoninus Pius, Marcus Aurelius), and the Severans gave the Mediterranean peace, prosperity, and a remarkable degree of cultural integration. Latin spread, Roman law unified commercial life, and a network of paved roads — the famous Appian Way was the first of many — tied the empire together.

The Roman Empire is the setting for most of the stories people know: the eruption of Vesuvius in 79 CE that buried Pompeii and Herculaneum; the building of the Colosseum in Rome; the daily routine of the Roman baths; the bloody spectacles of the Roman Gladiators; the philosophical meditations of the emperor Marcus Aurelius.

The Late Empire and Fall (180 – 476 CE, in the West)

After Marcus Aurelius’s death, the empire began to face a series of crises: plague, barbarian invasions, economic decline, civil war, and a slow loss of legitimacy. Diocletian divided the empire into eastern and western halves in 285 CE, and Constantine legalized Christianity and moved the capital east to Byzantium (Constantinople) in 330 CE. The western Roman Empire fell in 476 CE when the Germanic king Odoacer deposed the last emperor, Romulus Augustulus. The eastern half, known to us as the Byzantine Empire, endured for almost another thousand years.

Roman Government

Rome’s contribution to political thought is rivaled only by Athens’. The Republic invented the separation of powers, the rule of law, the idea of citizenship, and the senate as a governing body. The Empire pioneered the apparatus of the modern bureaucratic state: the civil service, the standing army, the professional tax collectors, the codified law, and the imperial cult that would later be inherited (in part) by the Christian church.

Many of the most familiar Latin political terms — senator, consul, praetor, dictator, republic, senate, constitution — come from the Republic, and the founding fathers of the United States were, in part, reaching back to Roman precedent when they used them.

Roman Law

Roman law is, with Greek philosophy, one of the two great intellectual inheritances of the modern West. By the second century CE, the jurists of the Empire had developed a sophisticated body of civil law — the Corpus Juris Civilis — that distinguished between public and private law, person and thing, contract and tort. Most modern European legal systems, and the civil-law tradition generally, descend from Roman law. So does much of the legal vocabulary of English-speaking countries, even where the common law tradition is dominant.

Roman Engineering

The Romans built to last. They perfected the use of arches, domes, and concrete and used them to construct roads, bridges, aqueducts, sewers, harbors, and buildings across three continents. You can read the technical details in Roman Engineering, but the basic fact is that Roman roads, aqueducts, and amphitheaters were still in active use a thousand years after the empire fell.

The empire’s most famous buildings include the Colosseum, the Pantheon (the world’s largest unreinforced concrete dome until the modern era), and the great imperial forums around the Roman Forum. The first great road out of Rome, the Appian Way, was begun in 312 BCE and is still partly paved in its original stones.

Roman Life

For the majority of Romans, life was hard. Most people were farmers, artisans, or slaves. The urban poor of Rome itself lived in crowded tenements (insulae) and survived on the dole of free grain distributed by the state. The wealthy lived in luxurious domus houses with atriums, frescoes, mosaics, and private baths.

The rhythm of the Roman day was set by the markets, the public baths, the public games, the religious festivals, and the political meetings in the Forum. Food was bread, olives, cheese, garum (a fermented fish sauce), and wine. The Roman baths were not just for bathing but for socializing, exercising, and reading. Gladiatorial games in the Colosseum were the most popular entertainment in the city; provincial cities had their own smaller amphitheaters.

For the full picture, see Daily Life in Ancient Rome.

Roman Religion and the Rise of Christianity

The traditional Roman religion was a bundle of household gods, civic rites, and imported cults: the Lares of the household, the Capitoline Triad of Jupiter, Juno, and Minerva, the Greek pantheon adopted almost wholesale, the Egyptian cult of Isis, the Persian cult of Mithras.

Christianity began as a small Jewish sect in first-century Palestine, spread rapidly through the Jewish diaspora of the Greek east, and was carried west by merchants, missionaries, and soldiers. The Romans sporadically persecuted Christians until the emperor Constantine converted in 312 CE and shortly afterward issued the Edict of Milan, granting Christianity legal status. Within a century it had become the official religion of the empire.

The Roman Military

The Roman army was, for centuries, the most professional and effective fighting force in the Mediterranean. The Roman legion — a heavy infantry formation built around the sword, the javelin, and disciplined maneuver — conquered the Mediterranean basin and held it for hundreds of years. You can read about Roman enemies and tactics in the Ancient Warfare pillar, the Punic Wars cluster, and the Hannibal Barca long-tail.

Why Rome Still Matters

The Roman legacy is everywhere, even where we don’t see it. Romance languages (Italian, French, Spanish, Portuguese, Romanian) are descendants of Latin. The legal systems of most of Europe, Latin America, and much of Africa descend from Roman law. The Roman Catholic Church preserves Roman administrative structures and uses Latin as its official language. The architectural vocabulary of columns, domes, and arches is Roman. The political vocabulary of “senate,” “republic,” and “imperial” is Roman. The very idea of “Europe” was, in part, a Roman idea.

The Roman Army in Detail

The Roman army was, for centuries, the most professional and most effective fighting force in the western world. The early Roman army was a militia of citizen-soldiers, raised each year for a single campaign, and commanded by the consuls. The army of the late Republic was a professional force, raised for long periods of service, loyal to its commanders, and capable of long campaigns in Spain, Africa, Greece, and Asia. The army of the Empire was a standing professional force, recruited from the Roman citizens of Italy and the provinces, and stationed on the frontiers of the empire.

The basic unit of the Roman army was the legion, originally about 4,500 heavy infantry supported by 300 cavalry. In the late Republic, the legion was reorganized into 10 cohorts, each of 3 maniples, each maniple of 2 centuries. In the early Empire, the century became the basic tactical unit, and the cohort became the basic administrative unit. The legion was supported by auxiliary forces, recruited from the non-citizen subjects of the empire, and organized in units of similar size to the legion but with different equipment.

The legionary was equipped with the gladius (a short stabbing sword), two pila (heavy javelins), a large rectangular scutum (shield), and a distinctive lorica segmentata (segmented metal plate armor). The standard armament of the auxiliary was different: the auxiliary infantry used the spatha (a long cutting sword), the hasta (a thrusting spear), and a round shield. The Roman cavalry was equipped with the spatha, a round or oval shield, and a galea (helmet). The auxiliary archers and slingers provided the long-range support.

The Roman army was famous for its discipline, its training, and its engineering. The Roman legion was a self-contained engineering unit, capable of building roads, bridges, forts, and siege works. The famous Roman road system, the Roman camps (the castra), the Roman siege works, and the Roman frontier fortifications are all products of the engineering skill of the army.

The Roman soldier served for twenty-five years in the early Empire, and was rewarded with a grant of land and a sum of money at the end of his service. The veterans formed the backbone of the Roman municipal aristocracy, and they were the source of the political and military leaders of the later empire. The Roman army was, in many ways, the foundation of the Roman state, and the loyalty of the army was the single most important political fact of the later empire.

Roman Culture in the High Empire

The Roman culture of the high Empire was a complex blend of Italian, Greek, and provincial elements. The Roman elite was bilingual in Latin and Greek, and the Roman cultural world included the entire Greek-speaking eastern Mediterranean as well as the Latin-speaking west. The great Roman writers of the high Empire — Virgil, Horace, Ovid, Livy, Ovid, Tacitus, Pliny the Elder, Pliny the Younger, Suetonius, Juvenal, Martial, Statius — wrote in a sophisticated literary culture that was deeply influenced by the Greek tradition.

The Roman visual arts were similarly sophisticated. The Roman portraiture of the Republic and early Empire is famous for its stark, veristic style, designed to emphasize the dignity and the seriousness of the Roman citizen. The Roman architecture of the high Empire — the Pantheon, the Colosseum, the Forum, the imperial palaces on the Palatine, the great imperial baths — was a brilliant combination of Greek and Etruscan traditions, the arch and the vault, and the new technology of concrete.

The Roman religion of the high Empire was equally complex. The traditional Roman religion continued, with its household gods, its civic rites, and its imported cults. The emperor was worshipped as a god, and the imperial cult was the central religious fact of the Empire. The mystery religions of the East — the cult of Isis, the cult of Mithras, the cult of Cybele — spread rapidly across the western provinces. Judaism, a legal religion under the Roman law, was tolerated but periodically restricted. Christianity, a small Jewish sect in the first century, grew slowly at first and then rapidly, and by the time of Constantine in the early fourth century it had become the dominant religion of the empire.

The Crisis and Fall of the Roman Empire

The Roman Empire began to decline in the third century, and the western half finally fell in 476 CE. The reasons for the decline have been debated for centuries, and there is no single, agreed-upon explanation. The most commonly cited factors include:

The Germanic invasions. The Gothic, Vandal, Frankish, and other Germanic peoples began to push into the Roman frontiers in the third century, and the pressure increased throughout the fourth and fifth centuries. The Visigoths sacked Rome in 410 CE, the Vandals sacked it in 455 CE, and the Germanic king Odoacer deposed the last western emperor in 476 CE.
The economic crisis. The third century saw a severe economic crisis, marked by the debasement of the currency, the inflation of prices, the decline of trade, and the collapse of the tax system. The reforms of Diocletian and Constantine stabilized the economy, but at the cost of a much heavier tax burden on the population.
The military crisis. The third century saw the rapid turnover of emperors, most of them killed by their own soldiers. The empire was saved by the reforms of Diocletian and Constantine, but the army was now heavily dependent on Germanic mercenaries, and the loyalty of the army was no longer to the empire but to individual commanders.
The political crisis. The Roman political system of the early Empire, based on the emperor, the Senate, and the bureaucracy, gradually broke down in the third century. The empire was divided into two halves in 285 CE, and the western half was never again able to reunite.
The religious crisis. The Christianization of the empire, beginning with Constantine in the early fourth century, transformed the Roman religious and political life. The old pagan temples were closed, the old religious practices were suppressed, and the church gradually took over many of the social and political functions of the state.
The environmental crisis. The Roman world suffered from a series of environmental problems: deforestation, soil exhaustion, climate change, and the spread of malaria. The combination of these problems weakened the agricultural base of the empire and made it more vulnerable to the other crises.

The fall of the western Roman Empire was a turning point in the history of the world. The eastern half of the empire, with its capital at Constantinople, survived for almost another thousand years. The western half was gradually taken over by the Germanic kingdoms, which preserved some Roman institutions and blended them with their own. The Catholic Church, which had become the dominant religious institution of the western empire, survived the fall of the political state and became the most important institution of the early medieval west.