Religion in RTW

[Setzer]

Typically, when I conquer a city, I don't bother changing its religion. It's too much trouble to change a city from Christianity to Paganism, or from Zoroastrianism. Are there any advantages from having a unified religion?
How can one ensure their generals or heirs will follow a certain religion? And how can one most easily change religions without sparking a civil war?

[Brother-Captain Gaius]

Cities have a public order bonus if their religion matches the State's/governor's, and a penalty if they differ. I maintain the True Roman Ways by sending my Christian generals off with hordes of ragtag mercenaries on suicide slash'n'burn campaigns, ensuring they are not able to taint the right and proper devotion to Jupiter Optimus Maximus.

Changing religions can usually be done fairly bloodlessly, but you need money, troops, and characters of the desired religion. Open the settlement details tab to see the exact effects of everything on a city's religion, and play with it from there until you get a manageable shift to the desired religion.

[2000AD]

I find changing the religion of a town to be quite simple. Just demolish the existing temple and build yours ASAP and keepa couple of characters in the region. YOu'll be getting 15-20% or more convrersion in no time, and you should also be getting at least one 5% bonus for neighbouring region of same religion.

You'll have high unrest for a few turns, but since you just invaded you should have a sizable garrison there. Really the only thing that can hinder you is a load of neighbours.