Two hundred years of Han rule are interrupted briefly (in CE 9-24 by Wang Mang, a reformer), then restored for another two hundred years.

The Han rulers, however, are unable to adjust to what centralization has wrought: a growing population, increasing wealth and resultant financial difficulties and rivalries, and ever-more complex political institutions.

Riddled with the corruption characteristic of the dynastic cycle, by CE 220 the Han empire collapses.