According to the legend, Rome was founded on the Palatine Hill on April 21, 753 BC, by Romulus who also became the first king of Rome. The legend is not all wrong. The first traces of human settlement in the area have been found on the western slope of the Palatine Hill, dating from the 10th century BC, while the first evidence of the existence of a city is from the middle of the 8th century BC.

The city soon encompassed the adjacent Capitoline Hill and the drained lowland between the hills became the Forum Romanum. This became the political and economic centre of the city for all antiquity, while the Capitoline Hill became the religious centre. Later the rest of the Seven Hills of Rome became part of the town. For most of the republican era the city remained within the ancient Severian Walls and only in the 1st century BC the city started to grown larger. Three centuries later the city covered the area within the Aurelian Walls which remained the largest extent of the town until the 19th century.