I would really discourage people from looking for answers to things like this on Wikipedia. It is absolutely riddled with errors. It worries me that, increasingly, Wikipedia is regarded as not only the first place to look for information but the sole repository of knowledge. The idea that, once you've exhausted Wikipedia, your only recourse is to ask a question in this forum is quite scary. I've even had students citing Wikipedia as a source in their essays!
[Xanikk999] What's your definition of an "absolute monarch"? The last British monarch to overrule parliament was Queen Anne, so she might be the one.
[Orthodox Warrior] I'm not sure what your question is, but it sounds like you're thinking of the Battle of the River Frigidus. This happened in AD 394, nearly sixty years after Constantine's death. It was fought between Theodosius I and the western usurper Eugenius. It was a battle for control of the empire, not a religious battle. However, Eugenius' army contained many pagan mercenaries, while Theodosius was the emperor who had made Christianity effectively the state religion, and so it was perceived at the time as the great final showdown between Christianity and paganism. Theodosius' victory was thus the victory of Christianity in the empire. It also made him sole ruler of the whole empire - the last man ever to rule an undivided Roman empire, although he did so for under a year.
Constantine did not make Christianity the official religion of the Roman empire. I don't know why everyone seems to think he did. He merely (officially) tolerated it and (unofficially) endorsed it. It was Theodosius who enforced it, in the 380s.
