AHC: Reverse the fates of Manichaeism and Christianity

[Whiteshore]

With a POD after the foundation of Manichaeism by Mani, come up with a scenario where Manichaeism is the world's largest religion with over a quarter of the world's population following it while Christianity is an extinct religion which is more or less a footnote in the history books even with how it had a vast range in Late Antiquity and the Middle Ages.

 

[CountPeter]

That's a fairly easy one by some accounts. Manichaeism was a major rival to Christianity by some accounts. Have Manichaeism be championed in the roman empire instead of Christianity and boom.