Two Byzantine Empire alternate history questions

May 2014
Here are two Byzantine Empire alternate history questions:

1. What if Emperor Manuel I had a son in the 1150s in place of one of his two daughters? That way, he would have had a son who would have been in his 20s instead of being a preteen at the time of his death.

Would this have resulted in a more stable Byzantine Empire after Manuel's death? Also, what other effects would this have had?

2. What if the Crusaders would not have sacked Constantinople during the Fourth Crusade in 1204?
Mar 2019
Victoria, Australia
I think that the empire would certainly have not diminished and been reduced as easily if the fourth crusade did actually as it was supposed to. It was a capable force and may have inflicted victory against numerous opponents but I do not think they would have been able to rescue or reestablish the crusader states. It may have given the Byzantines some well-needed breathing room.

As for Manuel I, I think it really depends on one factor: would that child be capable enough to lead by his own and well, or would he be an incompetent ruler or otherwise weak and be ruled by others. Kingdoms rise and fall under capable or incapable individuals. As for the consequences and anything else, I might just leave it there since that is not exactly where I am sufficiently knowledgeable.