Gaius Julius Caesar was a Roman general and statesman. A member of the First Triumvirate, Caesar led the Roman armies in the Gallic Wars before defeating his political rival Pompey in a civil war, and subsequently became dictator from 49 BCE until his assassination in 44 BCE. He played a critical role in the events that led to the demise of the Roman Republic and the rise of the Roman Empire.

Caesar’s gens, the Julii, were patricians—i.e., members of Rome’s original aristocracy, which had coalesced in the 4th century BCE with a number of leading plebeian (commoner) families to form the nobility that had been the governing class in Rome since then. By Caesar’s time, the number of surviving patrician gentes was small; and in the gens Julia the Caesares seem to have been the only surviving family. Though some of the most powerful noble families were patrician, patrician blood was no longer a political advantage; it was actually a handicap, since a patrician was debarred from holding the paraconstitutional but powerful office of tribune of the plebs. The Julii Caesares traced their lineage back to the goddess Venus, but the family was not snobbish or conservative-minded. It was also not rich or influential or even distinguished.

The date of Caesar birth has long been disputed. The day was July 12 or 13; the traditional (and perhaps most probable) year is 100 BCE; but if this date is correct, Caesar must have held each of his offices two years in advance of the legal minimum age. His father, Gaius Caesar, died when Caesar was but 16; his mother, Aurelia, was a notable woman.

In 84 BCE Caesar committed himself publicly to the radical side by marrying Cornelia, a daughter of Lucius Cornelius Cinna, a noble who was Marius’s associate in revolution. In 83 BCE Lucius Cornelius Sulla returned to Italy from the East and led the successful counter-revolution of 83–82 BCE; Sulla then ordered Caesar to divorce Cornelia. Caesar refused and came close to losing not only his property (such as it was) but his life as well. He found it advisable to remove himself from Italy and to do military service, first in the province of Asia and then in Cilicia.

In 78 BCE, after Sulla’s death, he returned to Rome and started on his political career in the conventional way, by acting as a prosecuting advocate—of course, in his case, against prominent Sullan counter-revolutionaries. His first target, Gnaeus Cornelius Dolabella, was defended by Quintus Hortensius, the leading advocate of the day, and was acquitted by the extortion-court jury, composed exclusively of senators.

Caesar then went to Rhodes to study oratory under a famous professor, Molon. En route he was captured by pirates (one of the symptoms of the anarchy into which the Roman nobility had allowed the Mediterranean world to fall). Caesar raised his ransom, raised a naval force, captured his captors, and had them crucified—all this as a private individual holding no public office. In 74 BCE, when Mithradates VI Eupator, king of Pontus, renewed war on the Romans, Caesar raised a private army to combat him

In his absence from Rome, Caesar was made a member of the politico-ecclesiastical college of pontifices; and on his return he gained one of the elective military tribuneships. Caesar now worked to undo the Sullan constitution in cooperation with Pompey (Gnaeus Pompeius), who had started his career as a lieutenant of Sulla but had changed sides since Sulla’s death. In 69 or 68 BCE Caesar was elected quaestor (the first rung on the Roman political ladder). In the same year his wife, Cornelia, and his aunt Julia, Marius’s widow, died. In public funeral orations in their honour, Caesar found opportunities for praising Cinna and Marius. Caesar afterward married Pompeia, a distant relative of Pompey. Caesar served his quaestorship in the province of Farther Spain (modern Andalusia and Portugal).

Caesar was elected one of the curule aediles for 65 BCE, and he celebrated his tenure of this office by unusually lavish expenditure with borrowed money. He was elected pontifex maximus in 63 BCE by a political dodge. By now he had become a controversial political figure. After the suppression of Catiline’s conspiracy in 63 BCE, Caesar, as well as the millionaire Marcus Licinius Crassus, was accused of complicity. It seems unlikely that either of them had committed himself to Catiline; but Caesar proposed in the Senate a more merciful alternative to the death penalty, which the consul Cicero was asking for the arrested conspirators. In the uproar in the Senate, Caesar’s motion was defeated.

Caesar was elected a praetor for 62 BCE. Toward the end of the year of his praetorship, a scandal was caused by Publius Clodius in Caesar’s house at the celebration there of the rites, for women only, of Bona Dea (a Roman deity of fruitfulness, both in the Earth and in women). Caesar consequently divorced Pompeia. He obtained the governorship of Farther Spain for 61–60 BCE. His creditors did not let him leave Rome until Crassus had gone bail for a quarter of his debts; but a military expedition beyond the northwest frontier of his province enabled Caesar to win loot for himself as well as for his soldiers, with a balance left over for the treasury. This partial financial recovery enabled him, after his return to Rome in 60 BCE, to stand for the consulship for 59 BCE.

The value of the consulship lay in the lucrative provincial governorship to which it would normally lead. On the eve of the consular elections for 59 BCE, the Senate sought to allot to the two future consuls for 59 BCE, as their proconsular provinces, the unprofitable supervision of forests and cattle trails in Italy. The Senate also secured by massive bribery the election of an anti-Caesarean, Marcus Calpurnius Bibulus. But they failed to prevent Caesar’s election as the other consul.

Caesar now succeeded in organizing an irresistible coalition of political bosses. Pompey had carried out his mission to put the East in order with notable success, but after his return to Italy and his disbandment of his army in 62 BCE, the Senate had thwarted him—particularly by preventing him from securing land allotments for his veterans. Caesar, who had assiduously cultivated Pompey’s friendship, now entered into a secret pact with him. Caesar’s master stroke was to persuade Crassus to join the partnership, the so-called first triumvirate. Crassus—like Pompey, a former lieutenant of Sulla—had been one of the most active of Pompey’s obstructors so far. Only Caesar, on good terms with both, was in a position to reconcile them. Early in 59 BCE, Pompey sealed his alliance with Caesar by marrying Caesar’s only child, Julia. Caesar married Calpurnia, daughter of Lucius Piso, who became consul in 58 BCE.

As consul, Caesar introduced a bill for the allotment of Roman public lands in Italy, on which the first charge was to be a provision for Pompey’s soldiers. The bill was vetoed by three tribunes of the plebeians, and Caesar’s colleague Bibulus announced his intention of preventing the transaction of public business by watching the skies for portents whenever the public assembly was convened. Caesar then cowed the opposition by employing some of Pompey’s veterans to make a riot, and the distribution was carried out. Pompey’s settlement of the East was ratified en bloc by an act negotiated by an agent of Caesar, the tribune of the plebs Publius Vatinius. Caesar himself initiated a noncontroversial and much-needed act for punishing misconduct by governors of provinces.

Another act negotiated by Vatinius gave Caesar Cisalpine Gaul (between the Alps, the Apennines, and the Adriatic) and Illyricum. His tenure was to last until February 28, 54 BCE. When the governor-designate of Transalpine Gaul suddenly died, this province, also, was assigned to Caesar at Pompey’s instance. Cisalpine Gaul gave Caesar a military recruiting ground; Transalpine Gaul gave him a springboard for conquests beyond Rome’s northwest frontier.

Between 58 and 50 BCE, Caesar conquered the rest of Gaul up to the left bank of the Rhine and subjugated it so effectively that it remained passive under Roman rule throughout the Roman civil wars between 49 and 31 BCE.

In 56 BCE the Veneti, in what is now southern Brittany, started a revolt in the northwest that was supported by the still unconquered Morini on the Gallic coast of the Strait of Dover and the Menapii along the south bank of the lower Rhine. Caesar reconquered the Veneti with some difficulty and treated them barbarously. He could not finish off the conquest of the Morini and Menapii before the end of the campaigning season of 56 BCE; and in the winter of 56–55 BCE the Menapii were temporarily expelled from their home by two immigrant German peoples, the Usipetes and Tencteri. These peoples were exterminated by Caesar in 55 BCE. In the same year he bridged the Rhine just below Koblenz to raid Germany on the other side of the river, and then crossed the Channel to raid Britain. In 54 BCE he raided Britain again and subdued a serious revolt in northeastern Gaul. In 53 BCE he subdued further revolts in Gaul and bridged the Rhine again for a second raid.

The crisis of Caesar’s Gallic war came in 52 BCE. The peoples of central Gaul found a national leader in the Arvernian Vercingetorix. They planned to cut off the Roman forces from Caesar, who had been wintering on the other side of the Alps. They even attempted to invade the western end of the old Roman province of Gallia Transalpina. Vercingetorix wanted to avoid pitched battles and sieges and to defeat the Romans by cutting off their supplies—partly by cavalry operations and partly by “scorched earth”—but he could not persuade his countrymen to adopt this painful policy wholeheartedly.

The Bituriges insisted on standing siege in their town Avaricum (Bourges), and Vercingetorix was unable to save it from being taken by storm within one month. Caesar then besieged Vercingetorix in Gergovia near modern Clermont-Ferrand. A Roman attempt to storm Gergovia was repulsed and resulted in heavy Roman losses—the first outright defeat that Caesar had suffered in Gaul. Caesar then defeated an attack on the Roman army on the march and was thus able to besiege Vercingetorix in Alesia, to the northwest of Dijon. Alesia, like Gergovia, was a position of great natural strength, and a large Gallic army came to relieve it; but this army was repulsed and dispersed by Caesar, and Vercingetorix then capitulated.

During the winter of 52–51 BCE and the campaigning season of 51 BCE, Caesar crushed a number of sporadic further revolts. He spent the year 50 BCE in organizing the newly conquered territory. After that, he was ready to settle his accounts with his opponents at home.

The main issue at hand in the lead-up to the war was how Caesar, who had been in Gaul for almost ten years before 49 BCE, was to be re-integrated into the political fabric of Rome after accumulating immense power and wealth in Gaul.

The main issue at hand in the lead-up to the war was how Caesar, who had been in Gaul for almost ten years before 49 BCE, was to be re-integrated into the political fabric of Rome after accumulating immense power and wealth in Gaul.

As 50 BCE progressed, fears of civil war grew; both Caesar and his opponents started building up troops in southern Gaul and northern Italy, respectively. In the autumn, Cicero and others sought disarmament by both Caesar and Pompey, and on December 1, 50 BCE this was formally proposed in the Senate. It received overwhelming support but was not passed when one of the consuls dissolved the meeting. That year, when a rumour came to Rome that Caesar was marching into Italy, both consuls instructed Pompey to defend Italy, a charge he accepted as a last resort. At the start of 49 BCE, Caesar's renewed offer that he and Pompey disarm was read to the Senate, which was rejected by the hardliners. A later compromise given privately to Pompey was also rejected at their insistence. On 7 January, his supportive tribunes were driven from Rome; the Senate then declared Caesar an enemy and it issued its senatus consultum ultimum.

Around January 10 or 11, 49 BCE, in response to the Senate's "final decree", Caesar crossed the Rubicon – the river defining the northern boundary of Italy – with a single legion, the Legio XIII Gemina, and ignited civil war. Upon crossing the Rubicon, Caesar, according to Plutarch and Suetonius, is supposed to have quoted the Athenian playwright Menander, in Greek, "let the die be cast". Pompey and many senators fled south, believing that Caesar was marching quickly for Rome. Caesar, after capturing communication routes to Rome, paused and opened negotiations, but they fell apart amid mutual distrust. Caesar responded by advancing south, seeking to capture Pompey to force a conference.

Pompey withdrew to Brundisium and was able to escape to Greece, abandoning Italy in face of Caesar's superior forces, evading Caesar's pursuit. Caesar stayed near Rome for about two weeks – during his stay his forceful seizure of the treasury over tribunician veto put the lie to his pro-tribunician war justifications – and left Lepidus in charge of Italy while he attacked Pompey's Spanish provinces. He defeated two of Pompey's legates at the Battle of Ilerda before forcing surrender of the third; his legates moved into Sicily and into Africa, though the African expedition failed. Returning to Rome in the autumn, Caesar had Lepidus, as praetor, bring a law appointing Caesar dictator to conduct the elections; he, along with Publius Servilius Isauricus, won the following elections and would serve as consuls for 48 BCE. Resigning the dictatorship after eleven days, Caesar then left Italy for Greece to stop Pompey's preparations, arriving in force in early 48 BCE.

Caesar besieged Pompey at Dyrrhachium, but Pompey was able to break out and force Caesar's forces to flee. Following Pompey southeast into Greece and to save one of his legates, he engaged and decisively defeated Pompey at Pharsalus on August 9 48 BCE. Pompey then fled for Egypt; Cato fled for Africa; others, like Cicero and Marcus Junius Brutus, begged for Caesar's pardon.

Pompey was killed when he arrived in Alexandria, the capital of Egypt. Caesar arrived three days later on October 2 48 BCE. Prevented from leaving the city by Etesian winds, Caesar decided to arbitrate an Egyptian civil war between the child pharaoh Ptolemy XIII Theos Philopator and Cleopatra, his sister, wife, and co-regent queen. In late October 48 BCE, Caesar was appointed in absentia to a year-long dictatorship, after news of his victory at Pharsalus arrived to Rome. While in Alexandria, he started an affair with Cleopatra and withstood a siege by Ptolemy and his other sister Arsinoe until March 47 BCE. Reinforced by eastern client allies under Mithridates of Pergamum, he then defeated Ptolemy at the Battle of the Nile and installed Cleopatra as ruler. Caesar and Cleopatra celebrated the victory with a triumphal procession on the Nile; he stayed in Egypt with Cleopatra until June or July that year, though the relevant commentaries attributed to him give no such impression. Some time in late June, Cleopatra gave birth to a child by Caesar, called Caesarion.

When Caesar landed at Antioch, he learnt that during his time in Egypt, the king of what is now Crimea, Pharnaces, had attempted to seize his father's kingdom of Pontus across the Black Sea. His invasion had swept aside Caesar's legates and the local client kings but Caesar engaged him at Zela and defeated him immediately, leading Caesar to write veni, vidi, vici ("I came, I saw, I conquered"), Pompey's previous victories over such poor enemies. He then left quickly for Italy.

Caesar's absence from Italy put Mark Antony, as magister equitum, in charge. His rule was unpopular; Publius Cornelius Dolabella, serving as plebeian tribune in 47 BCE, agitated for debt relief and after that agitation got out of hand the senate moved for Antony to restore order. Delayed by a mutiny in southern Italy, he returned and suppressed the riots by force, along with his popularity. Cato had marched to Africa and there Metellus Scipio was in charge of the remaining republicans; they allied with Juba of Numidia; what used to be Pompey's fleet also raided the central Mediterranean islands. Caesar's governor in Spain, moreover, was sufficiently unpopular that the province revolted and switched to the republican side.

Caesar demoted Antony on his return and pacified the mutineers without violence before overseeing the election of the rest of the magistrates for 47 – no elections had been held – and also for those of 46 BCE. Caesar would serve with Lepidus as consul in 46; he borrowed money for the war, confiscated and sold the property of his enemies at fair prices, and then left for Africa on 25 December 47 BCE. Caesar's landing in Africa was marked with some difficulties establishing a beachhead and logistically. He was defeated by Titus Labienus at Ruspina on January 4 46 BCE and later took a rather cautious approach. After inducing some desertions from the republicans, Caesar ended up surrounded at Thapsus. His troops attacked prematurely on 6 April 46 BCE, starting a battle; they then won it and massacred the republican forces without quarter. Marching on Utica, where Cato commanded, Caesar arrived to find that Cato had killed himself rather than receive Caesar's clemency. Many of the remaining anti-Caesarian leaders, including Metellus Scipio and Juba, died by suicide shortly afterward. However, Labienus and two of Pompey's sons had taken Spain. Caesar started a process of annexing parts of Numidia and returned to Italy via Sardinia in June 46 BCE.

Caesar stayed in Italy to celebrate four triumphs in late September, supposedly over four foreign enemies: Gaul, Egypt, Pharnaces (Asia), and Juba (Africa). He led Vercingetorix, Cleopatra's younger sister Arsinoe, and Juba's son before his chariot; Vercingetorix was executed. According to Appian, Caesar paraded pictures and models of his victories in the civil wars against his fellow Romans during the triumphs, to popular dismay. The soldiers were each given 24,000 sesterces (a lifetime's worth of pay); further games and celebrations were put on for the plebs. Near the end of the year, Caesar heard bad news from Spain and, with an army, left for the peninsula, leaving Lepidus in charge as magister equitum.

At a bloody battle at Munda on March 17 45 BCE, Caesar narrowly found victory; his enemies were treated as rebels and he had them massacred. Labienus died on the field and one of Pompey's sons, Sextus, escaped but the war as effectively over. He remained in the province until June before setting out for Rome. He arrived in Rome in October of the same year and celebrated an unseemly triumph over fellow Romans. By this point he had started preparations for war on the Parthians to avenge Crassus' death at Carrhae in 53 BCE with wide-ranging objectives that would take him into Dacia for three or more years; it was set to start on March 18 44 BCE.

Between his crossing of the Rubicon in 49 BCE, and his assassination in 44 BCE, Caesar established a new constitution, which was intended to accomplish three separate goals. First, he wanted to suppress all armed resistance out in the provinces, and thus bring order back to the Republic. Second, he wanted to create a strong central government in Rome. Finally, he wanted to knit together all of the provinces into a single cohesive unit.

The first goal was accomplished when Caesar defeated Pompey and his supporters. To accomplish the other two goals, he needed to ensure that his control over the government was undisputed, so he assumed these powers by increasing his own authority, and by decreasing the authority of Rome's other political institutions. Finally, he enacted a series of reforms that were meant to address several long-neglected issues, the most important of which was his reform of the calendar.

On the Ides of March (15 March; see Roman calendar) of 44 BCE, Caesar was due to appear at a session of the Senate. Several senators had conspired to assassinate Caesar. Mark Antony, having vaguely learned of the plot the night before from a terrified liberator named Servilius Casca, and fearing the worst, went to head Caesar off. The plotters, however, had anticipated this and, fearing that Antony would come to Caesar's aid, had arranged for Trebonius to intercept him just as he approached the portico of the Theatre of Pompey, where the session was to be held, and detain him outside. (Plutarch, however, assigns this action of delaying Antony to Brutus Albinus.) When he heard the commotion from the Senate chamber, Antony fled.

According to Plutarch, as Caesar arrived at the Senate, Tillius Cimber presented him with a petition to recall his exiled brother. The other conspirators crowded round to offer support. Both Plutarch and Suetonius say that Caesar waved him away, but Cimber grabbed his shoulders and pulled down Caesar's toga. Caesar then cried to Cimber, "Why, this is violence!" ("Ista quidem vis est!").

Casca simultaneously produced his dagger and made a glancing thrust at Caesar's neck. Caesar turned around quickly and caught Casca by the arm. According to Plutarch, he said in Latin, "Casca, you villain, what are you doing?" Casca, frightened, shouted, "Help, brother!" in Greek (, "adelphe, boethei"). Within moments, the entire group, including Brutus, was striking out at him. Caesar attempted to get away, but, blinded by blood, he tripped and fell; the men continued stabbing him as he lay defenceless on the lower steps of the portico. According to Eutropius, around 60 men participated in the assassination. He was stabbed 23 times.