Rome expanded its territory through military conquests between 264 BC and 44 BC, gaining control of the Mediterranean region. Its central location on the Tiber River in Italy allowed it to develop trade networks by sea and an extensive road system across its empire. Over time, Rome transitioned from a republic to an empire ruled by emperors like Augustus, Trajan, and Hadrian. The Roman economy was based on farming and trade, though inflation increased as the value of currency decreased under various emperors. Roman society was stratified, with patricians, plebeians, consuls, tribunes, and slaves filling different roles.