[RobbyS]

By the end of the First Century, the majority of Christians were gentiles, and Jewish Christians were no longer welcome in the synagogues.

[LostTribe]

>By the end of the First Century, the majority of Christians were gentiles,

The got off to a pretty good start with Jesus declaration:

Matthew 10:5 These twelve Jesus sent out and commanded them, saying: "Do not go into the way of the Gentiles, and do not enter a city of the Samaritans. 6 But go rather to the lost sheep of the house of Israel.

The Lost Tribes of Israel (aka Lost Sheep of The House of Israel) were dominant by now in Galatia and elsewhere north of the Med (known as The Celts), and being Israelites (but not Jews) were not considered to be "gentiles". They did however became the majority "gentile" Christians of which you speak, even to this day.

The semantics of the word "gentile", and who is using it to mean what, unfortunately confuses the issue. (As is the case with Israel and Israelite, the word meaning is very dependent upon context, which is related to time.)