Answer:
Ancient Roman society changed out of all recognition as the Romans conquered first Italy and then the Mediterranean world, and the very notion of what it was to be a Roman came to embrace all the peoples of the empire.
As in all pre-modern societies the economic base of the Roman society at all stages of its history remained agriculture; but on top of this an ever-more elaborate social organization grew up, to create one of the largest and most complex societies in the pre-industrial world.