The Roman Empire: A Complete History from Founding to Fall

Few civilizations in human history have left a mark as deep and as enduring as Rome. From a cluster of huts on the Palatine Hill to a state that ruled the entire Mediterranean basin, the story of Rome is the story of how a small Latin settlement came to define law, language, engineering, and political thought for more than two millennia. Rome is the foundation upon which Western civilization, the Christian Church, the concept of citizenship, and the very idea of Europe were built.

This article is a comprehensive overview. It traces the arc from the mythical founding of the city by Romulus and Remus through the Roman Republic, the conquests that built an empire, the long peace of the Pax Romana, the crisis of the third century, the Christian revolution under Constantine the Great, and finally the fall of the Western Roman Empire in 476 CE. Along the way, it points to deeper articles on each major era, each major figure, and each pivotal battle.

The Origins: Myth and Archaeology

Roman tradition, recorded most famously by Virgil in the Aeneid and by Livy in his history of the city, held that Rome was founded on 21 April 753 BCE by Romulus, the son of Mars and the Vestal Virgin Rhea Silvia. Romulus and his twin brother Remus, descendants of the Trojan hero Aeneas, were suckled by a she-wolf before founding the city. Romulus killed Remus and gave the city his name.

Modern archaeology tells a more complicated story. The earliest settlements on the Roman Forum and the Palatine date to roughly the 10th century BCE, with huts built on stilts above marshy ground. By the 8th century BCE these villages had grown into a loose federation of hilltop communities, and by the 6th century BCE they had been unified into a single city under the rule of Etruscan kings. The historical truth behind Rome’s origin story is therefore not a single act of foundation but a slow process of consolidation.

The last of the semi-legendary kings, Tarquinius Superbus, was overthrown around 509 BCE, an event the Romans considered the birth of their Republic. Whether the revolution was a popular uprising, an aristocratic coup, or a foreign invasion remains debated, but its consequences were revolutionary: power would henceforth be exercised not by kings but by elected magistrates, advised by a senate and constrained by written law.

The Roman Republic: A Century of Conquest

The Roman Republic was not, in its first centuries, a democracy. It was an oligarchy in which a small class of patrician families dominated the Roman Senate and the senior magistracies. The plebeians, the common people, fought a long political battle for access to office and to legal protections, eventually winning the codification of the laws in the Twelve Tables around 450 BCE and the right to hold the consulship in 366 BCE.

What transformed Rome from a city-state into an imperial power was the series of wars fought against Carthage, the great Phoenician colony of North Africa. The Punic Wars, fought across the Mediterranean between 264 and 146 BCE, were among the most brutal and consequential conflicts of the ancient Mediterranean. In the first war Rome won Sicily, Sardinia, and Corsica. In the second, after Hannibal crossed the Alps with his elephants and annihilated Roman armies at Lake Trasimene and Cannae, Rome ultimately prevailed. The third war ended with the complete destruction of Carthage in 146 BCE. By the time of the final victory over Carthage, Rome was the unrivalled master of the western Mediterranean.

The same generation that destroyed Carthage also destroyed Corinth, the great Greek city, and incorporated Greece into the Roman sphere. Within a single lifetime Rome had become a Mediterranean empire.

The Late Republic and the Crisis of Liberty

Wealth from conquest changed Roman society. Vast estates worked by slaves captured in war displaced small farmers, who migrated to the city and formed an urban underclass dependent on subsidized grain. Generals who had led armies across the Mediterranean became too powerful to be controlled by the Senate. Tiberius Gracchus, who tried to redistribute public land to the poor, was murdered in 133 BCE along with 300 of his supporters. A century of political violence began.

The fall of the Roman Republic was a slow process punctuated by civil wars. Gaius Marius reformed the army, allowing landless citizens to enlist, and thereby bound the loyalty of soldiers to their commanders rather than to the state. Sulla marched on Rome itself in 88 BCE and held a proscription in which hundreds of citizens were killed for their property. Pompey, Crassus, and Julius Caesar formed the First Triumvirate, an informal alliance that bypassed senatorial authority. Caesar crossed the Rubicon in 49 BCE, chased Pompey across the Mediterranean, and returned to Rome as perpetual dictator. He was assassinated on the Ides of March, 44 BCE.

A new round of civil wars followed Caesar’s death, ending only when Caesar’s adopted son Octavian defeated Mark Antony and Cleopatra at the Battle of Actium in 31 BCE. Octavian, now styled Augustus, became the first emperor in 27 BCE. The Republic had ended; the Empire had begun.

The Principate: Augustus and the Pax Romana

The reign of Augustus Caesar, from 27 BCE to 14 CE, marked one of the great turning points in Western history. Augustus was careful to preserve the forms of the Republic. The Senate continued to meet, magistrates continued to be elected, and the language of republican liberty was maintained. In reality, however, all real power was concentrated in the hands of the princeps, the “first citizen,” who held a bundle of overlapping offices and commanded every legion.

The century that followed Augustus’s reign is sometimes called the Pax Romana, the Roman Peace. It was a period in which the borders of the empire stabilized, the economy flourished, trade expanded, and the Mediterranean became, for the first time, a single unified market. Goods from Roman Britain traveled to Roman Egypt, and grain from Egypt fed the million inhabitants of Rome.

The Julio-Claudian dynasty ruled for almost a century after Augustus, ending with the suicide of Nero in 68 CE. The Flavian dynasty that followed began the Colosseum and pushed the empire to its greatest territorial extent by completing the conquest of Britain.

The Five Good Emperors of the second century — Nerva, Trajan, Hadrian, Antoninus Pius, and Marcus Aurelius — are often considered the high point of the imperial system. Trajan conquered Dacia (modern Romania) and reached the Persian Gulf, the farthest east Rome would ever push. Hadrian consolidated the empire behind fixed frontiers, most famously Hadrian’s Wall in northern Britain. Marcus Aurelius, the philosopher-emperor, spent most of his reign on the Danube fighting Germanic invasions.

The Crisis of the Third Century

The death of Marcus Aurelius in 180 CE marked the end of the Antonine age. His son Commodus, portrayed unforgettably by Joaquin Phoenix in the film Gladiator, was assassinated in 192 CE, and the empire plunged into a half-century of catastrophe known as the Crisis of the Third Century.

Between 235 and 284 CE, the empire saw at least 26 emperors, most of whom died violently. The Roman army became the kingmaker, raising and deposing emperors in rapid succession. Persia under the Sassanid dynasty pushed Rome out of Mesopotamia. Germanic tribes crossed the Rhine and the Danube. The Plague of Cyprian (249–262 CE, possibly a viral hemorrhagic fever) compounded the earlier Antonine Plague of 165–180 CE, with both pandemics together killing perhaps a quarter of the population in the worst-affected regions. Inflation spiraled as the silver content of the denarius collapsed to almost nothing.

The crisis ended only with the accession of Diocletian in 284 CE. Diocletian restored the empire’s finances, doubled the size of the army, and instituted the Tetrarchy, a system of four co-emperors intended to provide stable succession and to defend the vast frontiers.

The Christian Revolution and the Later Empire

The most consequential religious change in Roman history occurred under Constantine the Great. In 313 CE, Constantine and his co-emperor Licinius issued the Edict of Milan, granting legal tolerance to Christianity throughout the empire. In 325 CE, Constantine convened the Council of Nicaea, producing the Nicene Creed, the foundational statement of Christian orthodoxy. In 330 CE, he moved the capital of the empire from Rome to the old Greek colony of Byzantium, which he renamed Constantinople.

Christianity, once a persecuted Jewish sect, became the official religion of the empire within a single generation. The transformation was profound. Roman temples fell into ruin or were converted into churches. The Vestal Virgins lost their state funding. Christian bishops became powerful political figures. Latin ceased to be the universal language of the eastern provinces, where Greek remained dominant.

The fifth century was a slow catastrophe. The Visigoths sacked Rome in 410 CE under Alaric, an event that shocked the Mediterranean world. The Vandals sacked it again in 455 CE. In 476 CE, the Germanic chieftain Odoacer deposed the last western emperor, Romulus Augustulus, and sent the imperial regalia to Constantinople. The Western Roman Empire had ended.

The Survival of the East

The story did not end in 476. The Eastern Roman Empire, ruled from Constantinople, survived for almost another thousand years. Modern historians call it the Byzantine Empire, although its citizens always called themselves Romans. Under Justinian in the sixth century, Byzantine armies reconquered Italy, North Africa, and southern Spain. The Hagia Sophia, the greatest church of the Christian East, was completed in 537 CE.

Constantinople fell to the Ottoman Turks in 1453, and the last Roman emperor, Constantine XI, died fighting on the walls. With him, the Roman state, in one form or another, had lasted for 2,204 years from the legendary foundation by Romulus.

The Roman Legacy

The Romans left a legacy so pervasive that it is often invisible. The modern Romance languages — Italian, French, Spanish, Portuguese, Romanian — are direct descendants of the Latin language. The Roman legal tradition underlies the civil law systems of continental Europe, Latin America, and much of Africa and Asia. The Catholic Church, headquartered in Rome, adopted the Roman administrative model for its own dioceses and parishes. Republican political theory, from Machiavelli to the American Founding Fathers, drew heavily on Roman precedents.

Roman engineering survives in the physical fabric of Europe. Roman roads still form the basis of European highways. Roman aqueducts still carry water in Segovia and other cities. Roman concrete, the secret of which was only recently rediscovered, has lasted two thousand years underwater. The arch, the dome, the basilica, the triumphal arch — all are Roman inventions still in everyday use.

What Scholars Still Debate

How Roman the Roman Empire really was, and how uniformly its culture was imposed, is still argued. Greg Woolf (Rome: An Empire’s Story, 2012) has stressed the sheer unevenness of Romanization: in some provinces the Latin language and the Roman way of life took root within a generation or two; in others, local languages, gods, and political forms survived for centuries beneath a thin Roman veneer. Mary Beard (SPQR, 2015) has questioned the long-standing assumption that the rise of the empire is a single coherent story, and reads it instead as a series of improvised accommodations. A second debate concerns the end of the western empire. Peter Heather and Bryan Ward-Perkins continue to insist on a real collapse in the fifth century; Peter Brown and his followers prefer a story of transformation into the post-Roman kingdoms. The two positions are not as incompatible as they once seemed, but the older question — whether the fall of Rome was a catastrophe, a transition, or both at once — has lost none of its force.