According to the J*wish history, Christianity first spread around Jerusalem, then to Anatolia, Greece, what is now Italy, Gaul and the Mediterranean coast of Iberia. I do not believe that the first Christians were persecuted by Roman pagans, nor do I think that Christianity travelled as far as Iberia before the Vatican. How did Christianity spread? Where did they first start to spread?
That is fake for many reasons.
There's evidence that the gospels weren't written until early 2nd century (no Christian author referenced them in their works until Irenaeus in the mid-2nd century). The epistles of Paul were written earlier, since earlier Christian authors refer to them, but they never considered them scripture. They only considered the Old Testament as their scripture.
Anyway, since they didn't have an identifiable document of their faith, how would Romans target xians specifically? And how would xianity spread?
The Romans just considered the early xians a bizarre, subversive sect of Judaism (remember: the New Testament was not made canon yet and they only considered the Old Testament as scripture, just like the other jews). Xians were also known to cause trouble and resist authority, so there you have it: many of them were breaking the law and were punished for doing so. This isn't "persecution", it's punishment for causing problems.
What happened probably is most Romans were Pagans. There were a few subversive jews who were xians and some Gentiles who also accepted it, but not many. Romans generally made fun of xianity and saw as a religion of slaves. That is, until psychopathic Roman emperors like Constantine saw xianity as a great control tool to "unite" the Roman empire, so they heavily pushed xianity and that's how they "spread" it.
But even then, it was not fully accepted like people claim. There's evidence that they still persecuted Pagans in the Byzantine empire in the 9th-10th centuries, so Pagans existed until then. In Western Europe, there were Pagan sects even in the middle ages.
Another lie xians tell is that the Vikings immediately accepted xianity when they first encountered it the 11th century and they became xians out of their free will. What really happened? Most Vikings were still Pagans. Some of them just added the jewish god to their Norse Pantheon as just another Pagan god. If they immediately converted to xianity, there wouldn't be any need for King Olaf to murder and persecute Pagans.
From Rome to Norway you can see a pattern: a king/emperor converted to xianity then he persecuted Pagans and tried to force xianity on them.
Still, even with that, a Swedish author said that in Sweden they still practiced a form of Paganism and rune magick well until the 16th century and later. There are a few who still practice it today, and it was passed on to them from their parents, grandparents e.t.c.