Qin dynasty
Note: King Zhaoxiang of Qin (秦昭襄王) had already been ruling Qin for 51 years when Qin annihilated the Zhou dynasty; however the other six warring states were still independent regimes. Some Chinese historiographers thus used the next year (the 52nd year of King Zhaoxiang of Qin) as the official succession from the Zhou dynasty.
Duke Ai of Qin
Duke Ai of Qin (, died 501 BC) was from 536 to 501 BC the nineteenth ruler of the Zhou Dynasty state of Qin that eventually united China to become the Qin Dynasty. His ancestral name was Ying (嬴), and Duke Ai was his posthumous title. Duke Ai succeeded his father Duke Jing of Qin, who died in 537 BC, as ruler of Qin.