周世宗
Chai Rong was born in Xingzhou (邢州; modern Xingtai, Hebei). As a child he came to live with his aunt — a younger sister of his father Chai Shouli () — and her husband Guo Wei, an official in the Later Tang military. The Guos had no sons, so they adopted the quiet nephew as their own. The youngster grew up into a muscular young man skilled at mounted archery, while also possessing a basic understanding of Chinese classics, history, and the Huang-Lao philosophy.