<P> King Zhao's exceptionally long reign ended in 251 BC . His son King Xiaowen, already an old man, died just three days after his coronation and was succeeded by his son King Zhuangxiang of Qin . The new Qin king proceeded to conquer East Zhou, seven years after the fall of West Zhou . Thus the 800 - year Zhou dynasty, nominally China's longest - ruling regime, finally came to an end . </P> <P> Sima Qian contradicts himself regarding the ultimate fate of the East Zhou court . Chapter 4 (The Annals of Zhou) concludes with the sentence "thus the sacrifices of Zhou ended", but in the following chapter 5 (The Annals of Qin) we learn that "Qin did not prohibit their sacrifices; the Lord of Zhou was allotted a patch of land in Yangren where he could continue his ancestral sacrifices". </P> <P> King Zhuangxiang of Qin ruled for only three years . He was succeeded by his son Zheng, who unlike the two elderly kings that preceded him was only 13 years old at his coronation . As an adult Zheng would turn out to be a brilliant commander who, in the span of just nine years, unified China . </P> <P> In 230 BC, Qin conquered Han . Han, the weakest of the Seven Warring States, was adjacent to the much stronger Qin, and had suffered continuous assaults by Qin in earlier years of the Warring States period . This went on until Emperor Qin Shi Huang sent general Wang Jian to attack Zhao . King An of Han, frightened by the thought that Han would be the next target of the Qin state, immediately sent diplomats to surrender the entire kingdom without a fight, saving the Han populace from the terrible potential consequences of an unsuccessful resistance . </P>

Who won the civil wars of the warring states period in order to become the first emperor of china