A recent revelation in my religious studies has taken more than the usual amount of time to digest. The resulting effervescent fountain of nested implications has kept me busy for a while.
Possibly the biggest question for me has always been based on a need to understand how the whole of Western Europe voluntarily abandoned dozens of millenia of life-affirming cultural practice for the highly illogical and restrictive Christian faith. I simply could not comprehend, nor find any clear mention of, any time when the vast majority of Romans suddenly realized the error of generations of traditional faith.
The most common explanation I heard was that the pagans realized that their gods were just statues made of stone and converted to the One True God (TM). This insulting bit of tripe is far more revealing of the essential loss of practice and culture in the Christian world that they would not recognize or understand the importance or value of a devotional statue -- even when they themselves were surrounded by them! Over time, I began to understand that the process was frequently helped along at the point of the sword when simple economic implications were not enough to win conversion. But this was not enough to explain a generalized, casual dismissal of hoary traditions by the majority of the population.
A big part of my confusion was that I was seeking a direct developmental path that would have connected the original apostles of Jesus to the first Bishops of Rome. According to popular Christian history, Romans recognized Christianity because of the vast numbers of believers and/or because of significant conversions in the Great Houses.
Americans have seen the great marches in the '20s and the '60s, when tens and hundreds of thousands of people would march in the US capitol city to incite cultural change for equality and justice. In all of my studies of the origins of Christianity, I have not encountered even the boldest apologist who has ever suggested that tens of thousands of Christians had marched in Rome as a means to either increase their numbers or to demand recognition from the Emperor. Nothing like that could have ever happened without a major military confrontation -- and we'd certainly have many records of something like that!
So, even after I had accepted the fact that Christianity was wholly established and controlled by Roman Imperial interests, I was still seeking some major cultural shift in which people suddenly started to think or behave differently. Something had to demarcate the "start" of Christianity in a way that would clearly indicate its true origins. Then, another illusion was vanquished.
[Big revelation here:] There was no shift or change, because the establishment of Christianity required none for the average Roman citizen. In the Roman world, matters of theology, philosophy, culture, and religion had already been slowly winding towards the position it attained in about 325AD, when Christianity was defined. The Graeco-Jewish "Jesus Movement" was the lesser of a dozen major Asian "savior" cults that had seriously Balkanized the homogeneous and staid religious culture of the Roman Empire. In an effort to reduce internal turmoil and create a single, homogenized religious world again -- one in which Greek syncretic traditions combined the essential elements of all the conflicting "Savior" faiths -- Constantine mandated the creation of "Christianity" as a generic, Roman version of all of the competing faiths in the Empire. In a sense, this was more of an effort to establish the "facts on the ground" and to conform the core agreements between the various cults into Imperial law.
The preference of the 'Jesus the Nazarene' character over the competition was most likely due to the relative weakness of the Jesus movement in relation to the far-better-established Mithras, Isis, or Cybele cults -- these Jesus people would be most likely to compromise and "fit in" with the Imperial agenda. Otherwise, the elements of the faith blend well the generally established theology, philosophy, and culture of the Eastern Roman Empire, circa 300AD.
A review for the book, Oriental Religions in Roman Paganism by Franz Cumont is upcoming. This book, along with Werner Jaeger's Early Christianity and Greek Paideia, have made significant recent contributions in my understanding of the context of Roman religious culture from about 300BC to 300AD.