The western Yíng clan at Quanqiu were lords over the Xichui ("Western March") region west of Mount Long and served as a barrier for the Shang dynasty against invasions by the Western Rong barbarians. One of them, Elai, was killed defending King Zhou of Shang during the rebellion led by Ji Fa that established the Zhou dynasty. The Yíng clan was however allied with the politically influential marquesses of Shen, whom the Zhou monarch relied upon heavily to manage the Rong people, and was thus allowed to retain their lands and continued serving as an attached vassal under the Zhou dynasty. A younger son of line, Feizi, impressed King Xiao of Zhou so much with his horse breeding skills, that he was awarded a separate fief in the valley of Qin (present-day Qingshui and Zhangjiachuan County in Gansu) northeast of Quanqiu, and his seat was named Qinyi (in present-day Qingtingzhen, Qingshui County). Both branches of the western Yíng clan lived in the midst of the Rong tribes, sometimes fighting their armies and sometimes intermarrying with their kings.