Question

What was Justinian I's role in the decline of the Byzantine empire?

Answer 1

Though the Byzantine Empire reclaimed nearly everything that the Roman Empire had lost (thanks mostly to the skill of his generals) and that he also went on a building spree, he was terrible with money. One of the reasons that most of the gains earned by his armies were lost after his death was that there weren't enough soldiers to go around. Why? Because there wasn't enough money left in the coffers to pay for a bigger army.

Justinian's rule marked a high water moment for the empire in many ways, but financially, he left it poorer.