Originally Posted by WarChild

See, I'm interested specifically in Muslims because the core of the belief is so unmoving.

Races, for the most part, can blend in anywhere. People tend to blend, taking on some of the local traditions, mixing them with their own. At least that's what I've seen.

Religion, on the other hand, has a hard fast set of rules. You must do this, you must do that, and tends to cause islands of culture, which is in my mind disruptive to the existing culture. This causes tension.