Gao Gan
In 199, after Yuan Shao defeated Gongsun Zan at the Battle of Yijing and took over his territories, he planned to launch a campaign against the warlord Cao Cao, who controlled the figurehead Han emperor, Emperor Xian, and the Han central government. He put his eldest son Yuan Tan in charge of Qing Province, second son Yuan Xi in charge of You Province, nephew Gao Gan in charge of Bing Province, and started mobilising troops from his territories in preparation for the campaign. Xun Chen served as a strategist in Yuan Shao's camp during the Battle of Guandu.