HI
Christianity did not GET POWER with constatine they were taken over by the state, That is why they should no longer be considered representive of what true christians believe. All the wars you bang on about were launched by men for political reasons using religion as the lever.
Peace
You don't make Any sense at all. Popes could excommunicate Kingdoms, written down in Papal Bull for Queen Elizabeth, so that was a Spanish Crusade against England like those against the Muslims where captured lands are legally now yours. Churches owned looked like 25% of the land in Europe outright with bishoprics, patriarchies. Depending on feudal or imperial administration. The Church was established wing of government like executive, judicial, legislative. Nobles, Clergy, usually Burghers. Every victory, like William the Conqueror's, proclaimed only the Rule of Christ. To claim the Church got subsumed is Nonsense.
The Orthodox Churches could still banish in their respective administrative dominions, patriarchies, and do a synod to meet for some sort of group action. The Churches were government Establishment as the UK knows the Establishment of the Church of England and the Church of Scotland, which have each been influenced at points in time, between Catholic/Anglican/Presbyterian.
I figure this guy played Byzantium 1066-1444 incredibly successful run, when the game's end date should basically be the siege of Constantinople. You know the point is how Armenia, Georgia, Bulgaria, Serbia, spun-off either from the Muslim pressure or the European model, from an Orthodox system protecting alphabet, language, and heritage with the Greek Empire, better than say the Catholics there.