greece was then ruled by the roman empire, and many argue that rome conquered greece with its army, but greece conquered rome with its culture. the roman empire after the conquest of greece became a civilization known as the greco-roman (or greek-roman) civilization. when the roman empire collapsed, the greeks emerged as the ruling class of the byzantine empire, and the greek language became the official language of the empire, which included all the territories around the eastern mediterranean sea. it was then occupied by the ottoman empire for a period of 400 years. some areas of greece, like the second-largest city in the country, thessaloniki, were occupied for 500 years and became part of greece in the early 20th century.