How do other pretenders override my Dominion?

[Graeme Dice]

Originally posted by Nappa:
[QB]What exactly causes this to happen? if their dominion can never get above 10 and my dominion is 10 how can they overcome my dominion?

Every time a successful temple check occurs, and the province is at maximum dominion, it is likely that the dominion will spread to a neighbouring province. If you don't have enough temples to counteract this, then you will lose dominion in your provinces.

Also, how does blood sacrifice work? when I noticed this happening I started blood sacrifices like crazy and switched every priest to preaching and I still lost.

Blood sacrifice causes a temple check for every blood slave that is sacrificed.