How was all the land lost after Justinian death

i hope im right, and let me know if im wrong :)

Explanation:

At the time of Justinian's death, the Byzantine Empire reigned supreme as the largest and most powerful state in Europe. Debts incurred through war had left the empire in dire financial straits, however, and his successors were forced to heavily tax Byzantine citizens in order to keep the empire afloat.

a.   it resulted in widespread unemployment.