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.
Duke Xiang of Qin
Duke Xiang ruled during a time of turmoil. The Zhou Dynasty had been at war with the western Rong tribes since the time of Duke Xiang's grandfather Qin Zhong. Qin, being the westernmost of the Zhou states, bore the brunt of the fighting against the Rong. Soon after Duke Xiang ascended the throne, in 777 BC he married his younger sister Mu Ying to a Rong leader called King Feng (豐王) in an apparent attempt to make peace. The following year he moved the Qin capital eastward from Quanqiu (犬丘, also called Xichui, in present-day Li County, Gansu) to Qian (汧, in present-day Long County, Shaanxi). Soon afterwards Quanqiu fell to the Rong. Shifu, Duke Xiang's older brother who led the defence of Quanqiu, was captured by the Rong, but was released a year later.