Mongols

So, i am playing my campaign as a Sokotra. I conquered the arabian world and then got bored of nestorianism and changed to my own religion. My empire was slowly getting bigger and bigger. I conquered constantinopole, rome, mend the great schism, etc.. Than I started getting offers of vasalisation from kazachs and other steppe nations. So I Said to myself why not, I might as well conquer the world. And get my empire all the way to siberia and mongolia without any fighting.

Than things started to get really weird.Right before year 1200, pope called crusade on Rome. So I raised my armies there and waited for them to come. But catholics armies never came. The whole crusade was popes mercenaries spawning right in rome sieging it, getting destroyed in seconds. So I just waited on percentages of held objectives. But in the meantime on the other side of the realm - mongols. They started invasion of my empire right away. I didnt care about Siberia, so I just let them conquer those underdeveloped villages. But when they conquer like 15 of them and won the war, they just eat my whole empire. Miracously Temujin teleported all the way to my capitol in Cairo and sit on my throne. Rather than I, great emperor just said to myself - few villages in mongolia are lost to some horse guys - its over, lets surrender my whole empire to him.

I was baffled by this interaction so I save loaded. I thought about giving those siberians and mongols independence. But i didnt have save where i was not in crusade war. You cannot give independence while in war. So I just disbanded my armies in Italia to be prepared for temujin. In the meantime in Italia catholics were coming unlike before. But only in small armies - they never united and was destroyed by my fellow believers. And mongols just didnt came. So now I am waiting what will hapen. They could come any time till 1240 I think, so I will be prepared.