石敬瑭
The nomadic Khitan people were united under Yelü Abaoji, who founded the Liao dynasty in 907 and, from 917 to 928, tried seven times to take Youzhou. In 936, a rift in the Later Tang court allowed Yelü Abaoji to help another Shatuo Turk general Shi Jingtang found the third of the Five Dynasties, the Later Jin. Shi Jingtang then ceded sixteen prefectures across the northern frontier including Youzhou, Shunzhou (modern Shunyi), Tanzhou (modern Changping) and Ruzhou (modern Yanqing) to the Khitans' Liao dynasty.