A question about the nature of Islam in this timeline:

Given the rise of islam happened in the context of a still prominent Roman Empire, wouldn't this cause serious butterflies to the faith, if it even exists?  Islam may in this world have come to being by a different prophet from a different tribe even if Islam in these sense of being a unifying faith among the arabic tribes derived from judeo-christian thought still is around.  While they likely still will write in Arabic and some of the athestetics may be similiar (although I don't know if there will be mosques modelled after muhammed's house as there will in our world), the whole doctrine may be different from the Sunnis and Shias or those other schools of thought that fell into the wayside.  From a doctrinal standpoint I wonder if Islam at this point might as well be a "build your own Abrahamic faith"-type deal.

I have interest, but unsure where to go.  Although I do ask, are Knights a thing here?