杜佑
In 787, Du was recalled to Chang'an to serve as "Shangshu Zuo Cheng" (), one of the secretaries general of the executive bureau of government (尚書省, "Shangshu Sheng"). He was later made the governor (觀察使, "Guanchashi") of Shan Prefecture (陝州, in modern Sanmenxia, Henan) and then the military governor of Huainan Circuit. While he was serving there, his mother died, but Emperor Dezong recalled him from his mourning period to continue his service. In 800, after Zhang Jianfeng the military governor of neighboring Xusihao Circuit (徐泗濠, headquartered in modern Xuzhou, Jiangsu) died, the soldiers of Xusihao assassinated the acting military governor Zheng Tongcheng () and supported Zhang's son Zhang Yin () as his replacement. Emperor Dezong gave Du the additional post as military governor of Xusihao, gave him the honorary chancellor designation of "Tong Zhongshu Menxia Pingzhangshi" (), and ordered him to attack Xusihao's capital Xu Prefecture. Du sent his officer Meng Zhun () to attack Xu Prefecture, but Meng was defeated while trying to cross the Huai River. When another attack by Zhang Pi () the prefect of Si Prefecture (泗州, in modern Huai'an, Jiangsu) also failed to capture Xu Prefecture, Emperor Dezong was forced to make Zhang Yin the military prefect (團練使, "Tuanlianshi") of Xu Prefecture, but took the other two prefectures of the circuit and merged them into Huainan Circuit, under Du's command. (When one of Zhang Jianfeng's staff members, the future chancellor Li Fan, subsequently fled to Huainan's capital Yang Prefecture, one of Zhang Jianfeng's former subordinates, Du Jian (), falsely accused Li Fan of encouraging Zheng's assassination and the soldiers' support of Zhang Yin. Emperor Dezong, believing Du Jian's accusation, ordered Du You to execute Li, but at Du You's intercession, Li was spared.)