The first inhabitants of Rome built their villages on seven hills, close to a crossing place over the Tiber. Rome's legendary founder, Romulus, supposedly lived on the Palatine Hill.
During the 6th century BC these villages coalesced to form an urban nucleus. The Etruscans transformed its appearance; they drained the marshes and built the first bridge and monumental temple.
Republican Rome consisted of modest structures built of bricks and timber. The only large buildings were temples. In 378 BC the first stone defensive wall was built.
Augustus rebuilt the city in marble. He restored previous temples and added aqueducts, baths, warehouses and other public buildings. Many emperors followed his example and a new architectural tradition emerged.
The emperor Aurelian realized the danger posed by barbarian tribes on the Roman borders. Between AD 270 and 275 he altered the frontier and provided Rome with a new defensive wall.
