Every now and then someone mentions the disappearance of Christians in North Africa. Except for Egypt there was a population drop in North Africa, and most of the Christians disappeared leaving the territory to the hardier herdsmen who lived in the Atlas mountains.
Islam came later!
There are still Christians in Egypt!
France (along with most other Western European nations) has encouraged immigrants to maintain their own identity, language, and culture
This sounds a lot like what goes on in this country with the Mexicans....illegal or not.
The Christians of North Africa (present-day Tunisia-Algeria-Morocco) eventually disappeared, but I think it was not until much later (era of the Crusades) that they disappeared entirely. St. Louis IX of France died in Tunisia in 1270 while on a Crusade...it may have been even later than that that the native Christian population disappeared.