Antiquity History

Deep Dive · Ancient Rome

The Roman Republic: From Republic to Empire

The Roman Republic was the longest-lived constitutional regime of the ancient Western world. Established in 509 BCE after the expulsion of the last king, it endured for nearly five hundred years — a period in which Rome grew from a small Italian city-state into the master of the entire Mediterranean basin. The Republic invented the separation of powers, the rule of law, the citizen army, and the senate as a governing institution, and it gave the modern world much of its political vocabulary: senate, consul, praetor, dictator, republic, constitution, veto.

This cluster page tells the story of the Roman Republic: its constitution, its wars, its class struggles, and its eventual collapse into civil war and empire. It links out to the Roman Empire cluster, the Julius Caesar cluster, and the Punic Wars cluster.

The Founding of the Republic

Traditional Roman history, told by the writers Livy and Plutarch, dates the founding of the Republic to 509 BCE, when the last king, Tarquinius Superbus, was expelled by a coalition of Roman aristocrats led by Lucius Junius Brutus. The story is probably half legend, but the event is symbolically important: the Romans of the late Republic and Empire saw their ancestors as having overthrown monarchy in the sixth century BCE and replaced it with a constitutional government. The word res publica literally means “the public thing” or “the public affair.”

The first century of the Republic was dominated by the struggle between patricians (the old aristocratic families) and plebeians (the common people). The plebeians won a series of concessions, including the right to hold the consulship, the codification of Roman law in the Twelve Tables (c. 450 BCE), and the right to appeal from magistrates to the people (the Lex Hortensia of 287 BCE).

The Roman Constitution

The Republic’s constitution was a complex mixture of elected magistracies, advisory bodies, and popular assemblies. There were no political parties in the modern sense, but political life was organized around patronage networks and ideological factions (optimates and populares, roughly the conservatives and the populists).

The principal magistracies were:

The Senate (Senatus) was the most prestigious body. It was not elected but was composed of former magistrates, appointed for life by the censors. The Senate advised the magistrates, controlled state finances, set the agenda of the popular assemblies, and in practice ran the day-to-day government of the Republic.

The popular assemblies (comitia) elected the magistrates, voted on laws, and decided on war and peace. They met in several different forms, with different voting rules and different constituencies. The Centuriate Assembly was organized by wealth class and served as the principal legislative and electoral body. The Tribal Assembly was organized by geographic tribe and elected the tribunes of the plebs, the lower-class magistrates who could veto the actions of the other magistrates and propose legislation.

The Conquest of Italy (c. 500–270 BCE)

The first three centuries of the Republic were dominated by wars in Italy. Rome gradually defeated its Latin neighbors, the Volsci, the Aequi, the Etruscans, the Samnites, the Sabines, and other Italian peoples, and by 270 BCE had unified the Italian peninsula under Roman leadership. The defeated Italian peoples were bound to Rome by a series of alliances that gave them varying degrees of independence and varying obligations to provide troops. The Roman citizenship was eventually extended to all free inhabitants of Italy south of the Po River in the first century BCE.

The Punic Wars (264–146 BCE)

The long series of wars between Rome and Carthage, the Phoenician city-state in North Africa, were the turning point of Republican history. The First Punic War (264–241 BCE) gave Rome its first overseas possession, the island of Sicily. The Second Punic War (218–201 BCE), dominated by the Carthaginian general Hannibal Barca, was the most dangerous crisis in Roman history. The Third Punic War (149–146 BCE) ended with the total destruction of Carthage and the annexation of its territories as the Roman province of Africa. The full story is told in The Punic Wars.

The Eastern Conquest

In the same decades, Rome was drawn into the eastern Mediterranean. The kingdom of Macedon, the Greek leagues, the Seleucid Empire, and Ptolemaic Egypt were all eventually absorbed. The most famous moment was the Roman sack of Corinth in 146 BCE, in the same year as the destruction of Carthage; the Greek world was now under Roman rule.

The Late Republic and the Crisis of the First Century BCE

The conquest of the Mediterranean made Rome rich, but it also broke the political system of the Republic. The senatorial class grew fat on the spoils of war, while small Italian farmers were dispossessed by the great slave-worked estates of the new provinces. Slave revolts — most famously the revolt of Spartacus in 73–71 BCE — rocked the Italian peninsula. The armies of the late Republic were now professional forces, loyal to their generals rather than to the state, and ambitious generals like Marius, Sulla, Pompey, and Julius Caesar used them to fight civil wars.

The First Triumvirate, an informal alliance of Caesar, Pompey, and Crassus, broke apart after Crassus died at Carrhae in 53 BCE. Caesar conquered Gaul, crossed the Rubicon in 49 BCE, defeated Pompey at Pharsalus, and was made dictator perpetuo — dictator for life. On 15 March 44 BCE, he was assassinated in the Theatre of Pompey by a group of senators led by Brutus and Cassius. The date, the Ides of March, became one of the most famous in history (see The Ides of March). A long series of civil wars followed, ending in 27 BCE when Caesar’s adopted son Octavian became Augustus, the first Roman emperor, and the Republic formally ended.

The Legacy of the Republic

The Roman Republic gave the modern world much of its political vocabulary. The word republic itself is the English translation of res publica. The American founders, when they called their new nation a republic and its upper house a senate, were consciously reaching back to the Roman model. The American constitution, the concept of a veto, the separation of powers, the idea of a senate as a deliberative body, and the tribune of the people all derive from Roman Republican practice. The Roman Republic was also the first state in the Western tradition to codify its laws (the Twelve Tables), to use a written constitution, and to build a political culture around public debate and free speech.