Gai Yu
warlord
Gai Yu (Chinese: 蓋寓) (died 905), formally the Duke of Chengyang (成陽公), was a key strategist of Li Keyong, a major warlord late in the Chinese Tang dynasty.
Background
It is not known when Gai Yu was born, but it was known that he was from Wei Prefecture (蔚州, in modern Zhangjiakou, Hebei), and that both his grandfather Gai Zuo (蓋祚) and father Gai Qing (蓋慶) served as officer at Wei Prefecture. When the ethnically-Shatuo officer Li Keyong rose against Duan Wenchu (段文楚) the defender of Datong Circuit (大同, headquartered at Datong, Shanxi) (which Wei Prefecture belonged to) at Datong's capital Yun Prefecture (雲州) in 878, Gai was one of the proponents, and he became a close associate of Li's.
Services under Li Keyong
After Li Keyong resubmitted to Tang authority and was made the military governor (Jiedushi) of Yanmen Circuit (t 雁門道 or 鴈門道, s 雁门道, Yànmén Dào) around present-day Datong in 882, he made Gai Yu a base supervisor as well as the prefect of Lan Prefecture (嵐州, in modern Lüliang, Shanxi). After Li Keyong was later made the military governor of Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi), Gai continued as a base supervisor. It was said that Li Keyong consulted him on all important matters and listened to his suggestions, and that he accompanied Li Keyong on all campaigns.
In 885, after a dispute between the powerful eunuch Tian Lingzi and Li Keyong's ally Wang Chongrong the military governor of Huguo Circuit (護國, headquartered in modern Yuncheng, Shanxi) erupted into an armed conflict, Wang Chongrong's and Li Keyong's forces defeated the forces of Tian and his allies Zhu Mei the military governor of Jingnan Circuit (靜難, headquartered in modern Xianyang, Shaanxi) and Li Changfu the military governor of Fengxiang Circuit (鳳翔, headquartered in modern Baoji, Shaanxi). Fearful of Wang Chongrong's and Li Keyong's approaching forces, Tian took then-reigning Emperor Xizong and fled to Xingyuan (興元, in modern Hanzhong, Shaanxi). Zhu broke his relationship with Tian and Emperor Xizong, took over the imperial capital Chang'an, and instead supported Emperor Xizong's distant relative Li Yun the Prince of Xiang as the new emperor. Zhu elicited support for Li Yun from the various regional governors, and when his emissary reached Hedong, Gai pointed out that the people of the realm had blamed Li Keyong for chasing Emperor Xizong out of Chang'an and that the only way for Li Keyong to clear himself in their eyes would be to see to Zhu's and Li Yun's destruction.
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