what some people have reported is immortality being flaky when the dominion is 1. I know Cainehill had this happen to him a couple of times. Perhaps there is an error in the code which has it as greater than 1 instead of greater than or equal.
Originally posted by JJ_Colorado: Do you need positive dominion at beginning of turn, at end of turn, or both to let your immortal survive being killed?
Just at the end of a turn. When in doubt, check the battle replay. If your immortal doesn't get the friendly dominion morale bonus(Or stat bonus if a prophet or pretender), you're potentially screwed.
While I agree with the "friendly dominion bonus" method of checking, that's not much use while planning moves
I think you are however mistaken - I think the friendly dominion needs to be in place at the start of the turn, not the end of the turn, for dominion to work.
Affecting dominion is taken at the start of the turn for stat/hp -modifiers of pretenders and prophets, and I think although I am not sure that for immortality only the dominion at the end of the turn matters.
First one is easy to try out: attack with your pretender from positive dominion province to one with negative dominion, and you'll see he has bonus to hitpoints (and other things), but I don'tremember where I read the latter 'fact' about immortality&dominion.