Early career
Gaius Julius Caesar was born in July 100 BC into the Julii, a patrician family that traced its descent (according to its own genealogy) to Aeneas and ultimately to Venus. The family had not been politically prominent for several generations. Caesar’s father died when Caesar was 16. His early career involved military service in Asia and Cilicia, prosecution of corrupt governors, and the steady accumulation of political offices (quaestor, aedile, pontifex maximus, praetor) through the cursus honorum. He was a noted public orator and a substantial debtor — his political career was financed by Marcus Licinius Crassus, the richest man in Rome.
In 60 BC Caesar formed the First Triumvirate, an informal political alliance with Crassus and the senior general Gnaeus Pompeius Magnus (Pompey). The arrangement let Caesar secure the consulship for 59 BC and a five-year (later extended) governorship of Gaul.
The conquest of Gaul
Caesar’s Gallic Wars (58–50 BC) extended Roman rule from the Mediterranean coast to the Rhine, the Atlantic, and (briefly) across the English Channel. The campaign was sold to the Roman senate as defensive, but was substantively a war of conquest against the Celtic and Germanic peoples of modern France, Belgium, the Netherlands, Switzerland, and southern Germany. Caesar’s own account, the Commentarii de Bello Gallico, is the standard primary source — written in clear third-person Latin prose that has been used as a Latin teaching text for two thousand years.
The decisive engagement was the siege of Alesia in autumn 52 BC, at which Caesar’s army of 60,000 defeated a Gallic field army of approximately 250,000 under Vercingetorix while simultaneously besieging the fortress containing another 80,000. Vercingetorix surrendered and was held in Rome for six years before being ritually strangled at Caesar’s triumph in 46 BC.
The Gallic wars killed by ancient estimates approximately one million Gauls and enslaved another million. The campaign also gave Caesar one of the largest, most experienced, and most personally loyal armies in the Roman world.
Civil war
Crassus died at Carrhae in 53 BC. Pompey, the surviving member of the triumvirate, broke with Caesar through the late 50s. The Roman senate ordered Caesar to disband his army and return to Rome as a private citizen. He refused. On 10 or 11 January 49 BC Caesar led the 13th Legion across the Rubicon, the small river marking the boundary between his province and Italy proper, initiating civil war. (The phrase “crossing the Rubicon” enters subsequent European political vocabulary from this moment.) The phrase he reportedly said as he crossed — alea iacta est, “the die is cast” — is attested in Suetonius writing 150 years later.
The civil war lasted four years and ranged across Italy, Spain, Greece, Egypt, North Africa, and Asia. Pompey was defeated at Pharsalus in northern Greece in August 48 BC and fled to Egypt, where he was murdered by court officials on arrival. Caesar reached Alexandria in pursuit and intervened in the Ptolemaic succession war, supporting Cleopatra VII against her brother Ptolemy XIII. The docks and grain warehouses of Alexandria were burned during the fighting — the event that gave rise to the (partial) tradition that Caesar burned the Library of Alexandria.
The republican forces continued to resist. Caesar defeated them at Thapsus in North Africa (April 46 BC) and Munda in Spain (March 45 BC).
Dictatorship and assassination
Caesar’s accumulation of unprecedented constitutional offices — consul, dictator, censor, pontifex maximus, tribunicia potestas — culminated in February 44 BC with the Senate’s vote of dictator perpetuo, “dictator for life.” This effectively ended the Republican constitutional fiction that he was a temporary office-holder. A group of senators including Marcus Junius Brutus, Gaius Cassius Longinus, and approximately 60 others organized his assassination.
On the Ides of March, 15 March 44 BC, Caesar was stabbed 23 times in the Theatre of Pompey, where the Senate was temporarily meeting while the Curia was rebuilt. He died at the foot of a statue of Pompey, the rival he had defeated four years earlier. The Senate adjourned in panic.
Consequences
The assassination did not restore the Republic. Caesar’s adopted heir Gaius Octavius — the future Augustus — formed a new political coalition with Mark Antony and Marcus Aemilius Lepidus (the Second Triumvirate), prosecuted Caesar’s killers (Brutus and Cassius died at the battle of Philippi in 42 BC), and then turned on his colleagues. By 31 BC Octavian had defeated Antony and Cleopatra at Actium; by 27 BC he had taken the title Augustus and become the first Roman emperor. The Republic was over.
Caesar himself became a posthumous deity (Divus Iulius) — the first Roman to be officially deified — and gave his name to every subsequent Roman emperor (the title Caesar), to the Russian tsar and German Kaiser, and to the month of July (renamed from Quintilis in his honour).