[NOTE: I am not a historian, so don’t believe a word I’m saying. Do not use this as a source!]
Around 100 BC the practice of having professional soldiers was established in the Roman Empire. Earlier, the army consisted of free peasants who served the government of Rome. But now professional soldiers were working directly for the leader of the army.
Julius Caesar was one of those leaders, and around 50 BC, he defeated a Germanic attack on the empire. Also, he conquered all of Gallia (Regardless of what Asterix would have you believe). However, the Senate, spearheaded by Pompey, thought that Caesar had become too powerful. So, they ordered him back to Rome without his army. Caesar knew that without his men he would have been tried and sentenced for corruption. Hence, Caesar did the only logical thing he could’ve done. He ignored this command and marched to Rome with his forces, and started a civil war. (He lived long enough to become the villain). In a short time, he seized power. And, reluctantly, the Senate appointed Caesar as dictator of the Roman Empire.
For Caesar, it was important to get support from the people of Rome. He gave his soldiers a significant amount of land, distributed grain to the poor and organized horse races for entertainment.
But one day many in the Senate found that Caesar had become too powerful, and in year 44 BC he was murdered by a group of senators. But while he was being killed he never said “Et tu, Brute?” That was something Shakespear wrote almost 1700 years later.