Most of the discussions about a reverse outcome at Milvian Bridge i see here often focus on the development of christianity as a religion.
But, here, i'll like to ask: what are the effects of an absent constantinian restoration on the Roman Empire as a whole?
How would the empire be divided? Would a tetrarch like Maxentius or Licinius end up unifying the whole empire under his thumb, like Constantine IOTL, or is a divided empire more plausible?
I've seen some people bring up an earlier abandonment of Britain and germanic barbarians gradually chipping off roman territory in Gaul. Could this happen?
Would the sassanid persians end up deciding to venture into roman territory?
What about Byzantium? Without the upgrading of the city into the massive urban center that has been Constantinople IOTL (and still is, as Istanbul), what happens?
If the huns still come, then how will the non-christian romans react?