I would suggest that zoroaster's religion isn't monotheistic as there is (or was at some time) a possibility that ahura mazda's side could lose.
There seems to be a bit of confusion about whether ahura mazda is supreme or equally opposed to the other guy (i forget his name).
If they are equally opposed, which is my understanding, then there are multiple gods, only one good one, but still not monotheism. No self-respecting monotheist would have a God that wasn't supreme.
There seems to be a bit of confusion about whether ahura mazda is supreme or equally opposed to the other guy (i forget his name).
If they are equally opposed, which is my understanding, then there are multiple gods, only one good one, but still not monotheism. No self-respecting monotheist would have a God that wasn't supreme.