The Fall of the Roman Republic: From Republic to Empire

For four centuries, the Roman Republic had governed a city-state, an Italian confederation, and finally a Mediterranean empire. Its constitution of consuls, Senate, and popular assemblies had proved extraordinarily adaptable, its legions had conquered the known world, and its citizens had been the freest, most politically engaged people of the ancient Mediterranean. Yet within a single generation after the destruction of Carthage in 146 BCE, the Republic was in visible crisis, and within another hundred years it had ceased to exist. The Republic that had defeated Hannibal could not defeat its own generals.

The fall of the Roman Republic was not a single event but a slow process of constitutional erosion, political violence, and social transformation. It began with a reform movement, degenerated into civil war, and ended with the establishment of a monarchy in all but name. The story is one of the most dramatic in ancient history, and its actors — the Gracchi, Marius, Sulla, Pompey, Crassus, Julius Caesar, and finally Octavian — are among the most famous Romans who ever lived.

The Crisis of the Late Republic

The wealth that flowed into Rome after the conquest of the Mediterranean transformed Roman society. The old citizen-farmer-soldier, the backbone of the early Republic, was disappearing. Vast estates worked by slaves captured in war had driven small farmers off their land. The dispossessed poured into Rome, where they joined an urban underclass dependent on subsidized grain. The Roman Senate, drawn from the wealthy landowning class, had a direct interest in preserving the great estates. The army, increasingly a professional force, served for years at a time under commanders who rewarded soldiers with land and booty — shifting loyalty from state to general.

The Gracchi: Reform and Reaction

The first sign of serious political crisis came in 133 BCE, with the tribunate of Tiberius Sempronius Gracchus. Gracchus was a young patrician of impeccable ancestry who had been elected tribune of the plebs on a platform of land reform. The problem he addressed was real: centuries of war had concentrated public land in the hands of the rich, while the small farmers who had once formed the backbone of the legions were being squeezed off their plots. Gracchus proposed a law limiting the amount of public land any individual could hold and redistributing the surplus to the poor.

The Senate opposed the bill. Gracchus took his case to the people, passed the law over senatorial objection, and was then killed, along with 300 of his supporters, in a riot organized by his fellow tribunes and the consul. He was the first Roman senator to die in domestic political violence in centuries.

His younger brother Gaius Gracchus took up the reform program ten years later. Gaius was a more sophisticated politician than Tiberius, and his program went further: land redistribution, subsidized grain, the building of roads and granaries, the foundation of colonies, and the extension of citizenship to the Italian allies. He won the support of the equestrian order by transferring the courts from the senators to the equestrians, who had a long-standing grudge against the senatorial monopoly of juries. He was reelected tribune in 122 BCE but lost his third campaign in 121 BCE, and the Senate passed a senatus consultum ultimum, a “final decree” authorizing the consul to take whatever measures were necessary to protect the state. Gaius was killed in a riot, along with 3,000 of his followers. The senatorial reaction was brutal and thorough. The political violence of the next century would follow the precedent set by the murder of the Gracchi.

Marius and the Reform of the Army

The next great crisis came in 107 BCE, when the consul Gaius Marius was elected to deal with the war against Jugurtha, king of Numidia. Marius was a novus homo, a “new man” — the first in his family to reach the consulship — and a brilliant military commander. He opened recruitment to the landless poor, allowing citizens without property to enlist. This dramatically expanded the pool of recruits but had a profound consequence: soldiers who had no land of their own looked to their commanders to provide for them when discharged. Combined with terms of service stretching to sixteen or twenty years, Marius’s reforms turned the army into a professional force bound to its commander. Marius served five consecutive consulships, and retired in disgrace in 100 BCE.

Sulla and the First March on Rome

The crisis came to a head in 88 BCE, when the Senate gave the command of the war against Mithridates VI of Pontus to the consul Lucius Cornelius Sulla. The tribunes of the plebs transferred the command to Marius, an ally of the popular party. Sulla, who was still in Rome with his army preparing to march east, did something that no Roman had ever done before: he marched on the city itself. He occupied Rome, executed his political opponents, and secured his command.

It was the first time a Roman general had used the army to dictate to the state, and it set a precedent that would be followed, with increasing brutality, for the next fifty years. Sulla fought his war in the east, returned to Italy in 83 BCE, defeated his enemies in a civil war, and in 82 BCE was appointed dictator legibus faciendis et rei publicae constituendae, “dictator for the making of laws and the settling of the constitution.” He held the office without a colleague and without a time limit — a constitution within a constitution.

Sulla ruled Rome for two years with a hand of iron. He published proscription lists, naming his enemies and offering rewards to anyone who killed them. As many as 5,000 Roman citizens were murdered in the proscriptions, their property confiscated and their names erased from public memory. Sulla reformed the Senate, expanded the number of courts, and limited the powers of the tribunes. Then, in 79 BCE, having restored the Senate’s authority, he resigned the dictatorship and retired to his villa. He died a year later, and the Republic was left with a constitutional system that had been violated by the very man who had claimed to defend it.

Pompey, Crassus, and the First Triumvirate

The generation after Sulla saw the rise of three men whose combined power would overshadow the state. Gnaeus Pompeius Magnus, “Pompey the Great,” was a brilliant commander who had won his reputation as a teenager fighting for Sulla and had subsequently conquered the eastern Mediterranean. Marcus Licinius Crassus was the richest man in Rome, made his fortune from slave trading and silver mining, and had put down the Slave Revolt led by Spartacus in 71 BCE. Gaius Julius Caesar was a young patrician of old but impoverished family, an ambitious politician, commander, and writer.

In 60 BCE, Pompey, Crassus, and Caesar formed an informal alliance known as the First Triumvirate. The arrangement was entirely illegal — there was no office of “triumvir,” and the alliance was a private bargain — but the Senate was too weak to resist. Caesar was elected consul in 58 BCE and secured the governorship of Gaul, where for the next nine years he waged a brilliant series of campaigns that conquered the whole of modern France, defeated the Germanic chief Ariovistus, and twice invaded Britain. By 50 BCE Caesar was the most powerful general in Roman history. For more on his life, see Julius Caesar.

The triumvirate collapsed in 53 BCE, when Crassus was killed at the Battle of Carrhae fighting the Parthians. Pompey and Caesar were now the two most powerful men in the Republic, and they had become enemies. The Senate, hoping to reassert its authority, ordered Caesar to disband his army or be declared an enemy of the state.

The Rubicon and the Civil War

On 10 January 49 BCE, Caesar crossed the Rubicon, the small river that marked the boundary between his province of Gaul and Italy proper. To cross the Rubicon with an army was, by Roman law, an act of treason. Caesar knew that he was committing himself to civil war. According to Suetonius, he paused on the bank and said, Alea iacta est — “the die is cast.”

The civil war that followed was a long, complex, and bloody affair. Caesar, with a hardened veteran army of about 40,000 men, marched rapidly south and took Rome almost without resistance. Pompey withdrew to Greece, raised a new army, and was decisively defeated by Caesar at the Battle of Pharsalus in August 48 BCE. Pompey fled to Egypt, where he was murdered on the order of the young Ptolemaic pharaoh.

Caesar spent the next two years mopping up the Pompeian remnants, defeating them at the Battle of Thapsus in Africa in 46 BCE and at the Battle of Munda in Spain in 45 BCE. He returned to Rome as the unrivalled master of the Roman world, and in February 44 BCE was appointed dictator perpetuo, “dictator for life” — a title that was the very antithesis of republican government. For a deeper look at Caesar’s life, see the biography of Julius Caesar.

The Ides of March

On 15 March 44 BCE — the Ides of March — Caesar was assassinated in the Curia of Pompey by a group of senators led by Marcus Junius Brutus and Gaius Cassius Longinus. The conspirators claimed to be defending the Republic from tyranny, but they had no plan for what came next. The Roman crowd, far from rejoicing at the death of a tyrant, was furious. The conspirators were forced to flee Rome. Within a few years they were all dead, hunted down and killed by the very man whose adoptive father they had murdered: Octavian, the great-nephew and adopted heir of Caesar.

Octavian and the Second Triumvirate

Octavian, then 18 years old, was a sickly young man, but he had two immense advantages: he had been adopted by Caesar and was therefore the legal heir to his name, his fortune, and the loyalty of his veteran soldiers. He arrived in Italy, raised a private army, and in 43 BCE, with Marcus Antonius (Mark Antony) and Lepidus, formed the Second Triumvirate — a formal, extra-constitutional office. The new triumvirate was even more brutal than Sulla’s dictatorship. The proscriptions of 43 BCE claimed 3,000 Roman lives, including 300 senators. Among the victims was Cicero, the great orator, whose tongue and hands were nailed to the rostra in the Forum. The triumvirs divided the Roman world: Octavian took the west, Antony the east, and Lepidus Africa.

Actium and the End of the Republic

The Second Triumvirate was, like the first, a marriage of convenience, and it did not last. Lepidus was sidelined by 36 BCE, and the stage was set for a final confrontation between Octavian and Antony. Antony, who had gone east to reorganize the Greek provinces, had become the lover and political partner of Cleopatra VII of Egypt. The two of them posed as the new Dionysus and the new Isis, a divine couple to whom the East would be entrusted. Octavian, in Rome, portrayed Antony as a traitor dominated by a foreign queen.

The decisive battle came at Actium in western Greece on 2 September 31 BCE. Octavian’s admiral, Marcus Agrippa, commanded the fleet. Antony’s and Cleopatra’s combined fleet was larger, but it broke and fled in the middle of the battle. Cleopatra escaped with her treasure ships; Antony followed. Both committed suicide the following year in Alexandria. Octavian returned to Rome as the unrivalled master of the Roman world.

On 16 January 27 BCE, the Senate voted Octavian the title Augustus, “the revered one.” He was given the honorific princeps, “first citizen,” and a bundle of overlapping offices that gave him effective control of the state while preserving the forms of the Republic. The Senate continued to meet, magistrates continued to be elected, and consuls continued to be named. In reality, all real power was concentrated in the hands of the emperor. The Republic had ended; the Empire had begun. For Augustus’s full life, see the biography of Augustus Caesar.

Why the Republic Fell

The fall of the Roman Republic was the result of structural pressures that no constitution could have withstood indefinitely. Designed for a small city-state governed by a citizen-farmer-soldier aristocracy, the Republic had been stretched to govern a Mediterranean empire. The wealth of empire had destroyed the citizen-farmer-soldier; the armies of empire had become too professional to be commanded by annually elected magistrates; the wars of empire had produced too many victorious generals for the Senate to control. The Gracchi had tried to reform the system and had been murdered. Sulla had tried to restore the Senate and had marched on Rome. Caesar had tried to combine reform with personal rule and had been assassinated. Augustus had succeeded where they all failed, by preserving the forms of the Republic while concentrating its substance in his own hands.