Early life and career
Caesar was born into a
patrician family, the
Julia, which claimed descent from
Iulus, son of the legendary
Aeneas, supposedly the son of the goddess
cognomen "Caesar" originated, according to
Pliny the Elder, with an ancestor who was born by
Caesarean section (from the Latin verb to cut, caedere, caes-).
Historia Augusta suggests three
alternative explanations: that the first Caesar had a thick head of hair (Latin caesaries); that he had bright grey eyes (Latin oculis caesiis); or that he killed an elephant (caesai in Moorish) in battle.
 Caesar issued coins featuring images of elephants, suggesting that he favored this interpretation of his name.
Despite their ancient pedigree, the Julii Caesares were not especially politically influential, although they had enjoyed some revival of their political fortunes in the early 1st century BC.
 Caesar's father, also called
Gaius Julius Caesar, governed the province of
 and his sister
Julia, Caesar's aunt, married
Gaius Marius, one of the most prominent figures in the Republic.
 His mother,
Aurelia Cotta, came from an influential family. Little is recorded of Caesar's childhood.
In 85 BC, Caesar's father died suddenly,
 so Caesar was the head of the family at 16. His coming of age coincided with a
civil war between his uncle Gaius Marius and his rival
Lucius Cornelius Sulla. Both sides carried out bloody purges of their political opponents whenever they were in the ascendancy. Marius and his ally
Lucius Cornelius Cinna were in control of the city when Caesar was nominated to be the new
high priest of Jupiter,
 and he was married to Cinna's daughter
 Following Sulla's final victory, though, Caesar's connections to the old regime made him a target for the new one. He was stripped of his inheritance, his wife's dowry, and his priesthood, but he refused to divorce Cornelia and was forced to go into hiding.
 The threat against him was lifted by the intervention of his mother's family, which included supporters of Sulla, and the
Vestal Virgins. Sulla gave in reluctantly, and is said to have declared that he saw many a Marius in Caesar.
Caesar felt that it would be much safer far away from Sulla should the Dictator change his mind, so he left Rome and joined the army, serving under
Marcus Minucius Thermus in Asia and
Servilius Isauricus in Cilicia. He served with distinction, winning the
Civic Crown for his part in the
Siege of Mytilene. He went on a mission to
Bithynia to secure the assistance of King
Nicomedes's fleet, but he spent so long at Nicomedes' court that rumours arose of an affair with the king, which Caesar vehemently denied for the rest of his life.
 Ironically, the loss of his priesthood had allowed him to pursue a military career, as the high priest of Jupiter was not permitted to touch a horse, sleep three nights outside his own bed or one night outside Rome, or look upon an army.
Hearing of Sulla's death in 78 BC, Caesar felt safe enough to return to Rome. He lacked means since his inheritance was confiscated, but he acquired a modest house in
Subura, a lower-class neighbourhood of Rome.
 He turned to legal advocacy and became known for his exceptional oratory accompanied by impassioned gestures and a high-pitched voice, and ruthless prosecution of former governors notorious for extortion and corruption.
On the way across the
 Caesar was kidnapped by
pirates and held prisoner.
 He maintained an attitude of superiority throughout his captivity. The pirates demanded a ransom of 20
talents of silver, but he insisted that they ask for 50.
 After the ransom was paid, Caesar raised a fleet, pursued and captured the pirates, and imprisoned them. He had them crucified on his own authority, as he had promised while in captivity
—a promise that the pirates had taken as a joke. As a sign of leniency, he first had their throats cut. He was soon called back into military action in Asia, raising a band of
auxiliaries to repel an incursion from the east.
On his return to Rome, he was elected military
tribune, a first step in a political career. He was elected
quaestor for 69 BC,
 and during that year he delivered the
funeral oration for his aunt Julia, and included images of her husband Marius in the funeral procession, unseen since the days of Sulla. His wife Cornelia also died that year.
 Caesar went to serve his quaestorship in
Spain after her funeral, in the spring or early summer of 69 BC.
 While there, he is said to have encountered a statue of
Alexander the Great, and realised with dissatisfaction that he was now at an age when Alexander had the world at his feet, while he had achieved comparatively little. On his return in 67 BC,
 he married
Pompeia, a granddaughter of Sulla, whom he later divorced in 61 BC after her embroilment in the
Bona Dea scandal.
In 63 BC, he ran for election to the post of
Pontifex Maximus, chief priest of the Roman state religion. He ran against two powerful senators. Accusations of bribery were made by all sides. Caesar won comfortably, despite his opponents' greater experience and standing.
Cicero was consul that year, and he exposed
conspiracy to seize control of the republic; several senators accused Caesar of involvement in the plot.
After serving as
praetor in 62 BC, Caesar was appointed to govern
Hispania Ulterior (modern south-eastern Spain) as
 though some sources suggest that he held proconsular powers.
 He was still in considerable debt and needed to satisfy his creditors before he could leave. He turned to
Marcus Licinius Crassus, one of Rome's richest men. Crassus paid some of Caesar's debts and acted as guarantor for others, in return for political support in his opposition to the interests of
Pompey. Even so, to avoid becoming a private citizen and thus be open to prosecution for his debts, Caesar left for his province before his praetorship had ended. In Spain, he conquered two local tribes and was hailed as
imperator by his troops; he reformed the law regarding debts, and completed his governorship in high esteem.
Caesar was acclaimed
Imperator in 60 and 45 BC. In the Roman Republic, this was an honorary title assumed by certain military commanders. After an especially great victory, army troops in the field would proclaim their commander imperator, an acclamation necessary for a general to apply to the
Senate for a
triumph. However, he also wanted to stand for consul, the most senior magistracy in the republic. If he were to celebrate a triumph, he would have to remain a soldier and stay outside the city until the ceremony, but to stand for election he would need to lay down his command and enter Rome as a private citizen. He could not do both in the time available. He asked the senate for permission to stand in absentia, but Cato blocked the proposal. Faced with the choice between a triumph and the consulship, Caesar chose the consulship.