Rome's early history is shrouded in legend. According to Roman tradition, the city was founded by the twins Romulus and Remus on 21 April 753 BC. Archaeological evidence supports the view that Rome grew from pastoral settlements on the Palatine Hill built in the area of the future Roman Forum. While some archaeologists argue that Rome was indeed founded in the middle of the 8th century BC, the date is subject to controversy. The original settlement developed into the capital of the Roman Kingdom (ruled by a succession of seven kings, according to tradition), and then the Roman Republic (from 510 BC, governed by the Senate), and finally the Roman Empire (from 27 BC, ruled by an Emperor). This success depended on military conquest, commercial predominance, as well as selective assimilation of neighbouring civilisations, most notably the Etruscans and Greeks. From its foundation Rome, although losing occasional battles, had been undefeated in war until 386 BC, when it was briefly occupied by the Gauls. According to the legend, the Gauls offered to deliver Rome back to its people for a thousand pounds of gold, but the Romans refused, preferring to take back their city by force of arms rather than ever admitting defeat, after which the Romans recovered the city in the same year.
Roman dominance expanded over most of Europe and the shores of the Mediterranean Sea, while its population surpassed one million inhabitants. For almost a thousand years, Rome was the most politically important, richest, and largest city in the Western world. After the Empire started to decline and was split, it lost its capital status to Milan and then to Ravenna, and was surpassed in prestige by the Eastern capital Constantinople.