Final answer:
The transition of Rome from a republic to an empire occurred under the rule of Caesar Augustus in 27 BCE. The Republic, which lasted for roughly five centuries, was replaced by the Roman Empire, a political entity that would endure for centuries in the west and over a thousand years in the east.
Step-by-step explanation:
The transition of Rome from a republic to an empire occurred under the rule of Caesar Augustus in 27 BCE. After the death of Julius Caesar, Rome experienced a period of chaos and civil war, which led to the consolidation of power in the hands of strong military leaders.
Caesar Augustus declared himself Emperor and established the Roman Empire, which would last for almost five centuries in the west and over a thousand years in the east. Under the empire, Rome underwent significant territorial expansion, bringing it to the height of its power.
The Republic, which lasted for roughly five centuries, was a system of government where leaders were elected, and the Senate played a central role in the political culture of Rome. However, problems of wealth and power, as well as social and political instability, ultimately led to the collapse of the Republic and the transition to an imperial system.