The Israelite Christians fled Judea because they were getting harrassed and killed.
The Jews had convinced the Romans who ruled Judea that the Christians were trying to overthrow their empire.
That's exactly what the pharisees accused Jesus of in front of the Romans.
So where do you think the Christians will flee to? Another state of the Roman Empire?
They went outside of it.
Look at old maps of the Roman Empire. Where WEREN'T they established? North.
Also East, but there were too many mountains and they at first went by sea towards Antioch, and kept going North.
The Jews moved around too. They went wherever the Israelites went.
Why? Because they're sociopaths like their ancestor Esau.
Read Genesis about Esau and Jacob
They are parasitic to Christ's people.