Taking the Roman Empire as an example: Rome was by far the largest city in the empire at a total of ~1 million people. The others were estimated to have 500 thousand or fewer, with only 25-30% of the population living in a city at all.
Modern cities are enormous by comparison and our urbanization rate is completely flipped. 80% of people in the US live in a city, and we have 50 metro areas with a higher population than Rome had during the empire. Our largest metro area is New York/Newark/Jersey City at 20 million people, 20x that of imperial Rome.
And remember that Rome itself was an anomaly in its day, and the Roman Empire in general was an anomaly in European history.
Modern cities are enormous by comparison and our urbanization rate is completely flipped. 80% of people in the US live in a city, and we have 50 metro areas with a higher population than Rome had during the empire. Our largest metro area is New York/Newark/Jersey City at 20 million people, 20x that of imperial Rome.
And remember that Rome itself was an anomaly in its day, and the Roman Empire in general was an anomaly in European history.