Although very much separated on the eastern hemisphere, degradation of the Roman Empire and Han China came in similar waves; the results of the ruined civilizations, however, varied in impact of future civilization.
The decline and fall of a great of empire as the Roman would have to be a result of many strong tribulations. To start with, the spread of diseases such as smallpox vastly severed its numbers and even killed the emperor Marcus Aurelius. With a population of 60 million in 180 B.C. the Roman demographic was reduced by 25%. With a decreased populace, there became fewer defenders of the borders. Invasions increased in frequency, and war too took many Roman lives. In the Roman Empire, invasion was provided by Germanic tribes. Some craved bloodlust while others migrated after being invaded themselves by the Huns.
