User blog comment:LurkerLordB/Religion in a world without Christianity/@comment-1310192-20120424210917

Islam would not exist; yes, it was born amongst Pagan tribes, but the earliest drafts of Muhammad's faith were entirely based on Christianity. Without Christians spreading the word in Nabatea and Damascus Muhammad wouldn't have created a religion at all similar to what Islam is today. And the butterflies would probably make Muhammad not exist anyways.

No, the world would not look like Easternized World either, since you'd still have a powerful Roman Empire, Persia, et cetera. The point that Rome and Persia only became powerful under Christianity and Islam respectively is weird at its best and entirely delusional at its worst.