公孙瓒
Later Tian Yu served under Gongsun Zan as the Prefect of Dongzhou County (). One of Gongsun Zan's generals, Wang Men (), betrayed Gongsun Zan and joined Yuan Shao, and lead an attack on his former master with more than 10,000 troops. Tian Yu personally visited Wang Men and managed to shame the latter into retreating. Although Gongsun Zan knew of Tian Yu's intellect, he could not appoint important roles for Tian Yu. After Gongsun Zan's defeat, Tian Yu's friend Xianyu Fu hired him as an adjutant. He recommended that Xianyu Fu join Cao Cao, who subsequently hired Tian Yu as well in various official positions.