King Zhaoxiang of Qin
Reigning over 55 years, he was one of the longest-serving rulers during the Eastern Zhou Dynasty. Although making numerous policy mistakes during his later years, his aggressive territorial expansions were pivotal in consolidating the state of Qin as the dominant military powerhouse in the late Warring States period. It was the strategic dominance established during his reign that paved the way to Qin's eventual successful unification of China under his great-grandson, Ying Zheng.
Warring States period
The Warring States period () was an era in ancient Chinese history characterized by warfare, as well as bureaucratic and military reforms and consolidation. It followed the Spring and Autumn period and concluded with the Qin wars of conquest that saw the annexation of all other contender states, which ultimately led to the Qin state's victory in 221 BC as the first unified Chinese empire, known as the Qin dynasty. Although different scholars point toward different dates ranging from 481 BC to 403 BC as the true beginning of the Warring States, Sima Qian's choice of 475 BC is the most often cited. The Warring States era also overlaps with the second half of the Eastern Zhou dynasty, though the Chinese sovereign, known as the king of Zhou, ruled merely as a figurehead and served as a backdrop against the machinations of the warring states.