Ancient Rome was an Italiccivilizationthat began on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to become one of the largest empires in the ancient worldwith an estimated 50 to 90 million inhabitants (roughly 20% of the world's population and covering 6.5 million square kilometers (2.5 million sq mi) during its height between the first and second centuries AD.