[PvK]

A couple of incorrect answers were given below, unless things changed from Doms I:

1) A pretender can exist in a province with zero or negative dominion. They get penalties if they have to fight there, but they don't evaporate just from visiting a hostile dominion province. They just cannot exist is a world with none of their dominion anywhere in the world.

2) You can keep playing even if your god is dead and you have no priests or prophets or temples, nor your capital, as long as you have dominion. After all, your surviving followers might be able to recruit someone who could pray for the gods return, and recapture your capital. This actually happened to me in my first Doms I game - I tried to fight on for many turns without any of the above items (and no magic Users, either). I lost, but it let me squirm around for many turns after that happened.

PvK