Answer:
Even as Rome was under attack from outside forces, it was also crumbling from within because of a severe financial crisis. Constant wars and overspending had significantly lightened imperial coffers, and oppressive taxation and inflation had widened the gap between rich and poor. In the hope of avoiding the taxman, many members of the wealthy classes had even fled to the countryside and set up independent fiefdoms. At the same time, the empire was rocked by a labor deficit.
Hope this helps
--Jay
