I heard a while ago that part of the reason was that the Bosnian Christian church was weakened because accepting the Bogumils(sp?) angered both the orthodox and catholic neighbors. But I've seen offhand mentions on some other history subreddits that that was a misconsception.
So I'm asking you guys, What caused the greater conversion rate? Or were there some other factors that caused the modern discrepancy of muslim representation in the countries of the Balkans?
Adding another question:
Did the people in that area simply coalesce into religious groups after the fact? The muslims, the catholics, the orthodox. They seem to be the same physically and linguistically. Were they an occupied people that picked up a religious and moved around to be near others like them?