King Zhaoxiang of Qin
In 293 BC, East Zhou decided to ally itself with the states of Han and Wei, and sent troops to help attacking Qin. However, the combined forces of this alliance was destroyed at Yique by the young Qin general Bai Qi, with 240,000 men killed and their commander Gongsun Xi (公孫喜) captured and executed. After this loss, the East Zhou was unable to actively participate in future interstate struggles in any significant fashion.
In 256 BC, Duke Wu of West Zhou (西周武公) allied with other states to stop the Qin offensive on the Han city of Yangcheng. In retaliation, King Zhaoxiang of Qin sent general Jiu to invade West Zhou, successfully breaking into Wangcheng. The Duke Wu was taken to Xianyang to beg for mercy, conceding all his lands. Both King Nan and Duke Wu would die later that year, and the subsequent Duke of West Zhou, Duke Wen (西周文公), was exiled to Danhuju (憚狐聚). Because the Zhou royal court had fallen from power and King Nan had died without a successor, the Eastern Zhou Dynasty collapsed, ending 879 years of Zhou monarchy. The remaining East Zhou state was also conquered by Qin chancellor Lü Buwei seven years later in 249 BC during the reign of King Zhaoxiang's grandson King Zhuangxiang, after Duke Jing of East Zhou attempted to form an anti-Qin alliance with other states.
King Youmiu
The younger son of King Daoxiang of Zhao, Zhao Qian was nevertheless able to succeed before his elder brother Zhao Jia due to his mother Chang Hou's intervention. He inherited a country that was in danger of being conquered by the Qin state, as it had been since a defeat at the Battle of Changping in 260 BCE.