What was the biggest problem the Roman empire faced?

Answer 1

In the physical sense, the Answer is : Communication -- Although they built excellent roads to help alleviate somewhat, the serious disconnect between outlying territories and the Home province, it was and never could be, enough.

Answer 2

It is difficult to isolate one problem as the biggest one the Roman Empire and the severity of its problems changed over time. Invasions of the empire, military anarchy and economic decline were big problems in periods of its history.

The most troubled periods were the 3rd and 5th centuries AD. In what historians have called the Crisis of the Third Century there were invasions, military anarchy and economic collapse. There were many invasions in several parts of the vast frontiers of the empire. The Roman army managed to repel them, but the strain which this caused created military anarchy. Many of the emperors of this period were low birth men who rose from the military ranks, became generals and were proclaimed emperors by their troops, rather than aristocrats proclaimed by the senate. The army held political power. Moreover, there were many rebellions by various legions. As many as 35 usurper emperors were proclaimed emperors in military rebellions. They were all suppressed.

The problem of invasions re-emerged in the 5th century, so much so that the western part of the Roman Empire fell under the weight of the invasions by the Germanic peoples who gradually took over all its lands. As a result of this strain the empire lost political cohesion, military anarchy resumed and there were many usurpers.

In the Third century there was also an economic collapse due to hyperinflation. Many emperors had debased the Roman coins. The precious metal content was decreased, thereby devaluing the coins, which eventually became worthless. This led to hyperinflation. Trade collapsed as so did the urban economy which produced manufactures for long distance trade. Many people migrated to the countryside. Agriculture witched from commercial production for the cities to production for barter in the local economy. Many peasants and urban migrants were turned into servile labour by the owners of the large landed estates (this paved the way for serfdom in the Middle Ages). The problem of hyperinflation was eventually resolved. However, these economic changes could not be reversed.