What date did Julius Caesar start the Roman Empire?

Answer 1

He didn't. In its early days Rome was a typical city-state and had a territory of about 50 square miles. Its population of largely peasant farmers had small plots which could not bear subdivision amongs multiple sons, so expansion was required. Neighbouring cities were in the same predicament. So after the harvest was brought in and the the sacrifices made, each consul raised a legion, and these either defended their land from predators or captured adjacent land. As successful land pirates, they expanded into neighbouring territories, and over three centuries gained dominance over peninsular Italy and the islands. After defeating Carthage, both in Africa and Spain by the end of the third century BCE, they extended their influence there, and set out to teach Philp of Macedonia a lesson for siding with Carthage. This gave them influence in mainland Greece, and then they moved on to the post-Alexander Macedonian kingdoms of Asia Minor and Syria, with Pompey taking Jerusalem. By Julius' time, Rome was in complete control of Italy, with provinces scattered around the entire Mediterranean and tributary kingdoms further inland. Julius went on to consolidate Gaul, had a look at Britain and hated its weather, and was preparing to do in the Parthian empire when done in by his protegee Brutus and other conspirators. However the Roman Empire was long in place before he was born. Look for a long list of conquerors, with names like Scipio, Paulus, Sulla.