I have read some history books on Rome, and also books written by Romans, and I think it's a very broad process. If memory serves, it took 700 years for Rome to adopt Christianity, beginning with Emperor Constantine.

What I would reject however is the idea that this began with Pantheistic cultures, because it is a two sided thing. Yes, it did begin in some sense with pantheism, but equally, it also ended within pantheism.

Christianity formed itself around 20-40 years following the Octavian coup against the republic. Just like how the pantheists overthrew the Roman monarchy, so did they overthrow the Roman republic.

And Christianity was actually in its politically rooted purpose founded against this. It is precisely why it rejects things that we consider pagan today. Things such as extramarital affairs, orgies, excess, wealth, hedonism and similar things like that.

And then of course the broader sentiments about the evils of war, and the evils of poverty and the importance of forgiveness and community. This was a very big driving force of Christianity.

Because under pantheism, you were essentially living in a communal system. So you were the property of your family. That's why Romans had their family name first, and then often an individual name second.

EDIT: Actually, if memory serves, you had family name first, the name of your patriarch second, and your individual name last, which was often considered a nickname. So it speaks even more to this system.

This also meant that there was a significant patriarchal force within the Roman family, and why particularly older men had power and influence over women and younger men.

In fact prior to the Greek translation of the bible, the homophobic passage in Leviticus translated to "pederast" rather than "homosexual." Because they were talking specifically about this often very abusive power dynamic that older men had towards younger men.

So when Christians showed up and created these communities, then that meant people could escape from what was often very abusive and very oppressive family systems. It is also where the idea of where "Christian Names" comes from. Because the individual person is valued above the family.

So at this time several centuries onwards, this cultural force had already begun to dissolve Pantheism due to how the Roman religious authorities refused to address these contradictions.

And it is also precisely why the Holy Roman Empire and the Vatican have such flagrant hypocrisy in their revision and also contradiction of Biblical scripture.

The state religion was set up to consolidate these aristocratic traditions with Christianity in an effort to weaken the influences that Christian churches had over society. So it really was a very political tradeoff. If the aristocrats wanted to keep being warmongering hedonists, then they had to go to church on Sunday.

That's why the religion of Roman derived church systems seem so shallow and lacking in spiritual depth.

But it was fundamentally a rebellion against the wealthy landlords and senatorial oligarchy that had in effect abolished the power of the Equine class and the Popularaes in a series of very brutal political purges.

Because the Equines were like the middle class of Rome, and they had the Tribunes, which were local governments that actually had elected officials.

And this was driven by the Popularaes, who were the populist party. Most famous character in this party was of course Julius Caesar.

Then you had the Optimates, which in the modern translation more or less translates to "The Elitists." This is where the imperial status quo began. Casius, Brutus, Octavius, Cato and many of the other people involved in the coup were part of this movement.

Almost all of whom were landlords. Because Caesar imposed a series of rent moratoriums and slave reforms in an effort to combat the impoverished and oppressive conditions in the Roman suburas, which were the working class districts.

As you can imagine, this infuriated the senate. That is why they killed Caesar and abolished the democratic forces in Rome.

And Constantine of course appeared centuries later. And their adoption of Christianity was very reluctant. It happened as a concession to particularly the Germanic nations that had become very powerful and whose military actions had greatly weakened Rome.

And that is why the Holy Roman Empire was a Germanic successor to Rome which of course largely existed in Southern Europe as opposed to Western Europe.

So Christianity was not seen as compatible, in fact, quite the contrary. At this point it was seen as an existential threat to all these rich and militaristic Romans, and the idea was to co-opt Christianity, which they did very successfully.

Christianity did not enter the Roman state, rather, the Roman state entered Christianity. And it was quite detrimental in the centuries that followed.