i have long held that when the romans adopted christianity they fundamentally changed the religion, since you can't really go from "religion of the slaves/underclasses" to "religion of kings" without necessarily changing some aspects, but it's fascinating to see how that plays out a couple hundred years later in the early medieval when the Bulgars decide to go christian almost entirely as a political move -- their steppe rivals would have already been partially christian and they are definitely realizing that if you start worshipping this "jesus" guy then all these other powerful empires suddenly like you a lot more, and it would be nice to have that byzantine military behind you if you're facing off against the magyars or whatever
which is so interesting to me because it's this clear difference from the role of religion in antiquity (where i would argue it was generally speaking not considered THAT important in the role of proto-state-power) to the medieval/post-roman world where it's now a CRUCIAL part of "international" relations -- christianity has become a sort of cultural poker chip that you can acquire if you want to be on the side of the other "christian nations"
which is, of course, kind of ridiculous! right! like, "spirituality" or religion or whatever is as much a personal set of beliefs as it is a political one (though as i say that perhaps i'm showing my post-enlightenment cultural brainwashing anyway) and as soon as you start mixing the two things start getting really weird (which i would argue led to a lot of christian culture becoming so fragmented in the hundreds of years to come -- both for good and for ill)
but it IS undoubtedly this clear shift: religion that was once meant to explain the world, a sort of protoscience if you will, is now CLEARLY in the realm of statecraft, which just wasn't really how statecraft worked a few hundred years earlier.
like if nothing else this is making me even more sure in my general belief that so fucking much can happen in the period of only a few dozen years that the superstructures of daily life in a marxist sense are rendered absolutely alien to someone who lived only a generation or two ago
