I'm rather shocked by this lack of historical knowledge on a historical forum. The initial Moslem conquest were almost all from formerly Christian territory and the latter ones expanded into most of Spain as well as parts of France. There were even raids on the British Isles. The Crusades were in part a reaction to this. There is one point though that needs addressing. As far as I know the Koran is the only holy book that specifically calls for it's followers to spread the religion by means of the sword. Now Christianity did so but it is not supported by and indeed is antithetical to many of the teachings in the Bible. Early Judaism did call for a conquest of a specific area but that's a bit different than world conquest and it was only justified in that one incidence from what I've read. Extremist are the problem but there are some features of Islam that don't help.