Arch of Constantine

Column of TrayanThe legendary Romulus, in founding the future world capital in 753 BC, led his flock of shepherds and farmers up the Palatine Hill to protect them from the flooding Tiber river below as well as from the rival Etruscans across the Tiber (literally Trastevere) and Sabines on the Quirinal Hill.

From the beginning, Roman life was a fight, against nature and enemy tribes. Soon they spread over to the Capitoline Hill and Etruscan engineers drained the marsh in-between to create the Roman Forum. Here and in the adjoining areas they established the Republic with its Senate and rule of law, and later the Emperors built their Colosseum and staged their military Triumphs.
Mouth of Truth

This, then, was the center of civilization from the early days of Western European history until the fall of the Roman Empire in the 4C AD.

The Space-and-Time concept called Ancient Rome stretches for about a Millennium from the banks of the Tiber to the Colosseum, passing through the Forums and the Palaces, with rays stretching to the Imperial Mausoleums to the NorthWest and along the Appian Way to the South East.