Quote Originally Posted by Emperor Aurelius
Even though cultures change and such the Romans really never persecuted people because of their culture. Although Christianity(romans thought Christians were traitors and cannibals) and human sacrifice religions and the cult of dionysius were persecuted.
They of course exterminated Samnite culture, and Carthaginian, and of course the celtic druids who they completely wiped out...and pretty much anything else that they considered a threat. Persecution of the religious intelligentsia, with assimilation as the goal.

Regardless of whether or not there was organized persecution, there was lasting resentment to foreign cultures dominating an area. It fades with time. That is what the game attempts to represent. In RTW this is done by building new structures, and advancing to the next city level. The cultures that get the shaft are ones that don't have higher level administration buildings, because they get unrest that can never be eliminated through population growth. (It's sort of a "no going back" syndrome.) If anything, Rome has it easiest in this regard. They can build all of the higher level buildings.