As we all know, Christianity was adopted in the Sassanian Persian empire with the Sassanian Emperor converting to Christianity in 1086 AUC (333 AD) and Christianity becoming the official religion of the Sassanian Empire (albeit a form syncretized with Zoroastrianism with Zoroaster seen as a prophet of God) in 1137 AUC (384 AD) while Christians were heavily persecuted in the Roman Empire as the faith of Sol Invictus swept through the Empire and Christians were seen as Persian supporters, but what if the situation was reversed with Rome adopting Christianity and Persia heavily persecuting Christians as a response to the "enemy" power adopting Christianity? How would this affect the Migration Era? What PODs might be neccessary for such a scenario to occur?