The Romans originated in the city of Rome founded by Romulus and Remus on seven hills along the Tiber River. Rome transitioned from a monarchy to a republic and then an empire under Augustus Caesar. As an empire, Rome expanded across Western Europe and the Mediterranean through its powerful military. Roman society was divided into patricians, plebeians, and slaves. The Romans made advancements in architecture, constructing buildings like aqueducts, amphitheaters, and roads. Roman culture also flourished through sculptures, mosaics, and arts often inspired by Greek designs. Eventually, the Roman Empire declined due to economic troubles, overexpansion, and invasions by Germanic tribes.