With a focus on causation what are some of the explanations for the growing weakness of the byzantine empire in the centuries before 1450

For eleven centuries the Byzantine Empire resisted a series of conflicts that lasted in and out of its territory. Although considered one of the strongest States in the Mediterranean, the empire had to face several conflicts that weakened its power over the time.

One of the factors that influenced was the Fourth Crusade, which ended up disintegrating its military forces. Ottoman invasions  that occurred without success; and again in Constantinople (1453), this last one successfully, Constantinople was not able to resist the power of the invaders.

why do you think kush in nubia is not as well-known as egypt?

they died with poison from the god patrick