Gaius Julius Caesar is among the most written about people to have ever lived. He grew up in an aristocratic Roman family at a time when the Roman Republic was embroiled in intermittent infighting and unofficial civil wars. He became an agile politician and beloved general. In order to consolidate his power and to avoid prosecution by political enemies, he embarked on a lengthy military campaign in Gaul (a territory that is mostly modern-day France). It was a controversial war at the time, and many modern scholars argue it was in fact a Celtic genocide.
When the Senate ordered Caesar to surrender his army to the incoming governor and return to Rome, he opted to lead his legions into the city. This sparked an official civil war that ended in victory for Caesar. He ruled autocratically under several titles before eventually declaring himself Dictator for Life.
On March 15, 44 BC, a group of roughly 20 senators armed with knives attacked Caesar, murdering him on the Senate floor. They tried to argue the assassination was the only just response to a Roman attempting to make themselves a king, but Caesar’s popularity among the military and the lower classes endured.
The Civil War continued as generals, some friends of Caesar and others foes, tried to fill the void of a charismatic general who could overrule the Senate. Another contender for power in this era was Caesar’s nephew and adopted son, Gaius Octavius. Caesar adopted him posthumously in his will, after which Octavias took the name Julius Caesar for himself. After defeating both rebel generals, and the Roman Senate, he established the Roman Empire and took the name Augustus Caesar. His success was due in large part to political acumen. He was not a great soldier, so he sought out able generals like Marcus Aggripa as allies. He created an elaborate political system to allow the Senate the appearance of authority, while in fact, he and his successors held nearly absolute power.
Sources:
Gaius Julius Caesar: Civil War- Livius.org
Julius Caesar Revealed with Mary Beard- Odyssey
Celtic Holocaust- Hardcore History (free for a limited time)
Death Throes of the Republic- Hardcore History ($12 for the whole 6 part series, approx. 13 hours)