An empire can collapse in various of ways. For example, poor militaries, politics, a weak economy, or even because of the religion. For instance, militaries can cause a huge roll in why a union is dying. They can be inexperienced, or simply they do not have the loyalty to the empire they are fighting for. They can get sick from illnesses, like the plague.
The emperors can also play a big role in why an empire is receding.They can be too young or not be suitable for the duties to be a leader of an empire.A bunch