Unfortunately, Christians writers are extremely biased. We can see such a phenomenon
of partiality and censoreship in XX century. To take ceriously Christians writers it is the same as consider as reliable source "The Short Course of the
History of VKP(b)" (of course, communism is a political movement but with a certain features common with religeous ones). Looking further for a historical analogy, we can find a very recent example. When Soviet Empire collapsed, Moscow was inundated by missionaires of different religions ready to invest
good money to infiltrate the land. Was the
Roman Catholic
Church active? No, of course. Please, may your own suggestions on Churches which were the most active. But they did not succeed. The Russian Orthodox
Church, the traditional one, could rebuff all attacks, create a union with the power and restore its positions. It seems that similar processes one could expect in Ancient
Rome where Oriental religions were competing during the 2nd and 3rd century and in that period Christianism was not the dominating and the most attractive one. The difference is that the domestic religion was fractioned between numerous temples and failed down in
face of a totalitarian monotheism.