Emperor Ai of Tang
Li Zuo was born in 892, at the main palace at the Tang imperial capital Chang'an. His father Emperor Zhaozong was already emperor at that point, and he was Emperor Zhaozong's ninth son. His mother was Consort He, who had previously given birth to an older brother of his, Li Yu, Prince of De, who was Emperor Zhaozong's oldest son.
Guo Chongtao
The last Tang emperor, Emperor Ai, was forced to yield the throne to the major warlord (and Li Keyong's archrival) Zhu Quanzhong the military governor of Xuanwu Circuit (宣武, headquartered in modern Kaifeng, Henan) in 907, and Zhu declared himself emperor of a new Later Liang (as its Emperor Taizu). Li Keyong and several other major warlords (Li Maozhen, Wang Jian, and Yang Wo) refused to recognize the new Later Liang state, and effectively became rulers of their own states (in Li Keyong's case, Jin, as he carried the Tang-bestowed title of Prince of Jin). In 908, Li Keyong died and was succeeded as the Prince of Jin by his son Li Cunxu. Guo continued to serve Li Cunxu, and it was said that Li Cunxu valued his service.