Inspired of course by the King John thread ongoing what were the possible opportunities for nations and kingdoms and what not to have had a different religious development and I don't mean the BIG ones that are often enough discussed such as No Islam and Christianity and Rome.
For example, at one point during the Ottoman-Saffavid Wars there were several revolts within Ottoman and Anatolian Beylik territory that were Pro-Shia and even a few rumored Ottoman Royals that had become Shia. What if the Ottomans had become Shia? Well, certainly Shiaism would have a more prominent role but we would likely see more hard resistance from their Arab subjects.