李世勣
Li Yiyan himself passed the imperial examinations when he was young, and subsequently served as the sheriff of Taiyuan County. At that time, he served under the famed general Li Shiji, who served as the commandant at Bing Prefecture (并州, i.e., Taiyuan). Because of Li Shiji's accomplishments and reputation, the other subordinate officials were all fearful of him and dared not to speak on important matters with him, but Li Yiyan was said to be unafraid of the commandant and was willing to discuss matters of importance. As a result, Li Shiji respected him.