The first crusade is so sucessful that the christians take almost all of the Islamic lands.After many years ,the islam disappears.
This is impossible, even if we took all arabia and the middle east it still would be impossible to convert all muslims, it is ASB
First Crusade was barely able to take Jerusalem in first place, and it didn't take more than one century to have Latin states forming but coastal entities.
There is simply not enough men avaible, not enough ressources for this to happen : the lack of military reinforcement plagued Latins pretty much from the start.
The very best I could see happening without ASB (while quite unlikely) would be a Crusader conquest of Upper Egypt, and a Byzantine takeover of Anatolia as a by-product.
It depends on whether or not supernatural or otherwise impossible events happen in the POD or the TL. For example Tony Blair becoming President because God appointed him is ASB. Tony Blair becoming President because the US changes it's electoral laws to allow foreigners to run for office (or Tony Blair for some reason being born in America) is implausible, but not ASB.
I litterally said that "the very best" I could see happening, not that it would fill the OP. I still don't understand how it could be understood otherwise.Wrong. They aren't getting rid of Islam (and it's not even the goal of the first crusade) even if they took over Egypt and Arabia because of going overboard because
First, I'm not moving anything, so don't give me that.So there, stop moving implausible stuff to ASB. It's Type IV (utterly implausible AH)