I made a thread about this a few months ago, but i'd like to reiterate.
What if roman augustus Licinius had managed to defeat his brother-in-law Constantine sometime around the 310's?
What are the effects on...
The administration of the Roman Empire? How will Licinius decide to divide the empire?
Religion, especially? I hear that Licinius' image as a "fake christian" was mostly propaganda, as he co-authored the Edict of Milan, participated in ecclesiastic reforms like Constantine, had a christian wife, and, most interestingly, reportedly had a "war prayer" that was syncretic, in order to bring together his religiously diverse soldiers.
I also wonder, would there still be a Council of Nicaea? And if so, then how differently do you believe it would go?