A Boring Dystopia

Constantine literally started this modern Christiandom train

Constantine ended the institutional persecution of monotheists within the Roman empire. The apostolic church had been groving along well before that.

The end to formalized persecution gave Christians an opportunity to begin organizing openly - leading to the Ecumenical Councils that would define the church as an institution for the next two millennium. But the foundations were all in place well beforehand.

And thus Christian imperialism, conquest, subjugation, and terror has marched along ever since.

The Church, as a military power, has always been mediocre at best. Rome itself was gutted during the transfer of the court to Byzantium. And this laid the seeds for the Roman Orthodox split, which divides the church to this day.

The Western empire dissolved into feudal states, with Catholicism and the Church operating as a kind of diplomatic corps and patronage network for European aristocrats.

It wasn't until the emergence of Protestantism, following the failure by the Hapsbirgs to consolidate power during the 30 Years War, that capitalist expansion began to produce imperialism in the modern sense.

The conquest and subjection that followed was in pursuit of economic growth via slavery and plunder. The church existed to help rationalize these economic pursuits, but the priesthood was secondary to the merchant classes in actually executing it.