Yellow Turban Revolt
During the time of the Eastern Han dynasty (AD 25-220) the Chinese empire flowered.
Paper was invented, overseas trade initiated from Nan-hai (Canton) and military campaigns secured the Silk road in Sinkiang. China's economic resources, however, were exhausted by such campaigns. Taxation increased so much in the north, that many people migrated south to avoid it. Unrest increased among the impoverished peasants, until the revolt of the 'Yellow Turbans' broke out in AD 184.
The rebels wore yellow headpieces in a shade that symbolized the soil. The 'Yellow Turbans' were secret societies, backed by Taoist theories. The revolt was suppressed but the landlords who united to suppress the peasant rebellion joined with provincial governors in creating a threat to the government and the Han dynasty fell in AD 220.
After that more than three centuries followed in which there was no united government in China.