I saw on the first page the structure of the social and political life of Rome. Does this apply to Dacia as well? From my history knowledges, the Dacian society was not socially, politically, religiously compatible with the Roman society. It would be cool to have different structures for each civ (maybe with improvement packs?). So all the societies are Roman flavors?
All nations on the map are one of 3 different governments;
Republic
Monarchy (Includes Imperium, Dictatorship and Theocracy)
Tribe
It's possible for governments to convert to a different type of government. Taking Dacia as an example, a possible government progression could be:
Tribe > Military Republic > Dictatorship > Imperium
This evolution takes time and you have to fulfill certain goals before it's possible. Though, the game won't push you to achieve this goal, so it's up to you to advance your country as you see fit. Another thing I'll point out is that even though there are only 3 government types, each government has multiple forms. I can't remember them all but here's a few examples:
Republic (Military Republic, Oligarchic Republic, etc.)
Monarchy (Aristocratic Monarchy, Despotic Monarchy, etc.)
Tribe (Military Tribe, Civic Tribe and Trade Tribe)
Each form of government gives a different bonus.