What was the reason for the downfall of the Han Dynasty and The Roman Empire?

Was is partially invasion from barbarians?

Han Dynasty:
http://www.google.com/search?q=han+dynasty+downfall&ie=utf-8&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a

Roman Empire:
http://www.google.com/search?q=roman+empire+downfall&ie=utf-8&oe=utf-8&rls=org.mozilla:en-US:official&client=firefox-a

Good info in these results.

=)

what is a civil war

A civil war is a conflict that occurs within a country or region, usually between different groups or factions within the same nation. It typically involves armed battles and violence between the opposing sides, who may have differing political, social, or ideological views. Civil wars often stem from unresolved disputes over power, resources, territory, or other fundamental disagreements within a nation. The reasons for civil wars can vary widely, including political, economic, social, or ethnic factors. In some cases, a civil war may result in significant changes to the government or political structure of a country.