In a world without Islam (let's just say Muhammad dies a sickly infant or something along those lines), an assumption is that Christianity is a religion which does better without the Islamic Conquests with how the Middle East and North Africa were very much centers of Christianity prior to the rise of Islam and there were arguably more Christians in Asia than in Europe at this time period.
However, despite this, Christianity would certainly still not be the only religion in the world and face stiff competition from other religions which likewise would benefit from a world without Islam, so, the question is what kind of religions would there be in a world without Islam that could easily provide competition to Christianity, particularly with how Zoroastrianism and Buddhism could be seen as major competitors to Christianity in a world where Islam never existed. What kinds of religious wars could we see in this alternate history as the lack of Islam would certainly not bring an end to religious conflict? I personally see Buddhism, Zoroastrianism, and Manichaeism as the main potential competitors to Christianity in a world without Islam, especially with how Buddhism would be the other great proselytising religion that would be present in this alternate history, but any other thoughts on this question?
However, despite this, Christianity would certainly still not be the only religion in the world and face stiff competition from other religions which likewise would benefit from a world without Islam, so, the question is what kind of religions would there be in a world without Islam that could easily provide competition to Christianity, particularly with how Zoroastrianism and Buddhism could be seen as major competitors to Christianity in a world where Islam never existed. What kinds of religious wars could we see in this alternate history as the lack of Islam would certainly not bring an end to religious conflict? I personally see Buddhism, Zoroastrianism, and Manichaeism as the main potential competitors to Christianity in a world without Islam, especially with how Buddhism would be the other great proselytising religion that would be present in this alternate history, but any other thoughts on this question?