Rome began as a small city-state in Italy but eventually ruled the entire Mediterranean world due to its strategic location for trade. The Roman Republic was established in 509 BCE and featured a Senate of patricians and elected consuls, though plebeians demanded more equality over time. Rome expanded through military conquest during the Punic Wars against Carthage and by requiring submission of conquered peoples. The Roman Empire was established under Augustus after the transition from republic to empire under Julius Caesar, and it reached its greatest extent in the 2nd century CE before experiencing economic problems, military decline, and invasions that ultimately led to the fall of the Western Roman Empire in 476 CE.