Julius Caesar was born on the 13th day of the month Quintilis (now July) in the year of 100 B.C. His full name was Gaius Julius Caesar, the same as his father's. Gaius was his given name and Julius was his surname. Caesar was the name of one branch of the Julian family. It's original meaning was "hairy."
Caesar's family was not prominent, but they claimed to be descended from Venus. In spite of that fiction, Caesar was well connected through his relatives and received some important government assignments during his youth.
Among other projects, he was sent to bring back a fleet of ships from Nicomedes IV of Bithynia. He was also honored for bravery at the siege of Mytilene when he was only twenty years of age.
Several years later he left Rome to study in Rhodes but was captured by pirates while en route. His relatives paid a ransom and Caesar was released. He then recruited private troops, captured the pirates, and had them executed. Going on to Rhodes, his studies were soon interrupted by the outbreak of war with Mithradates VI of Pontus in 74. Caesar again gathered a force and participated in that war.
Caesar held a series of lesser political offices before becoming a Roman consul in 59 B.C. He then made an alliance now known as the "First Triumvirate" with two powerful military leaders, Pompey and Crassus. This First Triumvirate was very important in Rome's history.
When Crassus died the two remaining triumvirs were at loggerheads. Pompey had an army in the southern part of the Italian peninsula, including Rome. Caesar was in charge of an army in the north. He took his army across the Rubicon River (the dividing line between their regions) and thereby started a civil war.
Pompey was defeated. This left Caesar in charge of the military in Rome. It also signaled the end of the Roman Republic. The Republic was the period of Roman History when most of the expansion took place. It is referred to as the Republic because of it's Democratic style of government. Caesar was appointed dictator for a year starting in 49 B.C., for two years in 48 B.C., for ten years in 46 B.C. and finally dictator for life in 44 B.C. In that same year he was assassinated. Several years later his grand nephew Octavian became the first Roman Emperor. Octavian killed Caesar's only son, an illegitimate child bore by Cleopatra.