Speaking as a somewhat formally educated theologian here, the religion of Christianity, aka "Christian Orthodoxy" as it is know formally by "Orthodox theologians" or "Orthodox Christianity" by common folks, was started in 325 AD by the Emperor Constantine. Constantine convened the first of the Seven Church Councils and he presided over the first one in Nicea in 325 AD.
That was the beginning of government being involved in the control of church leaders who had believed in Jesus the Christ. It was Constantine's idea that his selected group of "early church fathers" create a creed which supposedly summarized their doctrinal beliefs. According to some sources, which I don't have current documentation on, the early church in the 1st 3 centuries did not think a creed was necessary; they believed faith alone was enough.
It was also his idea that they compile an anthology of books which were supposed to have been in the Pre-Jesus Period and also written during the first Century AD by the followers of Jesus the Christ. It took around 60 years or so before those "fathers" could even finally decide on what should be in that which we call a "Bible." Some of the accepted, aka canonized, works quote for sources which they rejected. In the short Epistle of Jude, the archangel Michael is disputing with the Devil over the body of Moses. The source of that was apparently from a work which was Jude's source called "The Assumption of Moses."