Why Do Empires Fall?

Throughout human history there have been empires that have risen, and although many have left their marks on the way the modern world is today, all just the same have fallen. Empires such as those conquered by Alexander the Great and Genghis Khan were very successful during their, in a sense, reign, however fell soon after their deaths. Why is it, that it is easier to create an empire than it is to make one last? First, the way empires are created is by one state conquering it’s weaker neighboring states, becoming stronger and more powerful, which allows it to continue to conquer and to continue to grow. However at what point do empires stop becoming a dominant power, which leads to their fall? One reason why an empire may fall is because

In many instances in history, empires met their end by civil wars fought over, who would be the next leader or king of the empire. Such as the Mongol Empire, also known as the Gigantic Empire, first established by Genghis Khan, who although after his death in 1227, the empire continued for another almost 200 years, started its slow decline when his three sons fought over who would rule. Even after Ogedei, the third son was chosen the fighting continued, as his sons and his brothers’ sons fought over who would be next, Ogedei’s sons arguing that the rule had to stay under Ogedei’s descendants while the others disagreed. Although in the end after Ogedei’s death the one who took reign was Ogedei’s widow, Toregene, who with the help of her assistant Fatima built churches all over the Mongol Empire. Just like the Mongol Empire many empires found their end, either because of battles waged between generals, if the previous ruler had no descendants, or between own relatives siblings fighting own sibling, or cousins against cousins. All fighting over who would be next. Not realizing that all their greed and all the fighting was putting an end to what they were fighting for, for how could they rule something that no longer