Historic city of Italy located on the Tiber River in central Italy. The historical site of Rome on the Seven Hills - the Aventine, Caelian, Capitoline, Esquiline, Palatine, Quirinal, and Viminal - was occupied as early as c 900 BC, but continuous settlement by Indo-European peoples did not take place until the beginning of the 1st millennium BC. By the early 6th century BC, a politically unified city had emerged. The Romans gradually conquered the Italian peninsula, extended their dominion over the entire Mediterranean, and expanded their empire into continental Europe toward the Atlantic. As the capital of this empire, Rome became the site of grandiose palaces, temples, public baths, theaters, stadiums, and other public buildings. The focus of the city was the Forum. Ancient Rome reached the peak of its grandeur and ancient population during the late 1st and early 2nd centuries AD.