Named for its origin in the state of Qin, a fief of the confederal Zhou dynasty which had endured for over five centuries—until 221 BC, when it assumed an imperial prerogative following its complete conquest of its rival states, a state of affairs that lasted until its collapse in 206 BC. It was formally established after the conquests in 221 BC, when Ying Zheng, who had become king of the Qin state in 246, declared himself to be "Shi Huangdi", the first emperor.
