The Zhou dynasty (c. 1050–256 BCE) had made the State of Qin in Western China as an outpost to breed horses and act as a defensive buffer against nomadic armies of the Rong, Qiang, and Di peoples. After conquering six Warring States (i.e. Han, Zhao, Wei, Chu, Yan, and Qi) by 221 BCE, the King of Qin, Ying Zheng, unified China under one empire divided into 36 centrally-controlled commanderies. With control over much of China proper, he affirmed his enhanced prestige by taking the unprecedented title "huangdi", or 'emperor', known thereafter as Qin Shi Huang (i.e. the first emperor of Qin). Han-era historians would accuse his regime of employing ruthless methods to preserve his rule.