There have been many Islams, the final accretion quite different from the earlier ones. For Islam itself is ending up being taken over (in the Sunni branch) by purists simply because they are more intolerant than the rest: the Wahhabis (aka Salafis), founders of Saudi Arabia, destroyed the shrines in most parts of what is now their country during the nineteenth century. They went on to impose the maximally intolerant rule in a manner that was later imitated by ISIS. Every single accretion of Salafism seems to exist to accommodate the most intolerant of its branches.
