Zhang Zhongwu () (died 849), formally Prince Zhuang of Lanling () (per the Old Book of Tang) or Duke Zhuang of Lanling () (per the New Book of Tang), was a Chinese military general and politician of the Tang Dynasty who governed Lulong Circuit (盧龍, headquartered in modern Beijing) as its military governor (Jiedushi) in de facto independence from the imperial government, but who followed imperial orders in campaigns against Huigu Khanate remnants, as well as Khitan, Xi, and Shiwei tribes. Background and seizure of Lulong Circuit It is not known when Zhang Zhongwu was born, but it is known that his family was from Fanyang, the capital of Lulong Circuit, which was then in de facto independence from the imperial government. His father Zhang Guangchao () was an officer of the Lulong army. It was said that in his youth, he studied the Zuo Zhuan version of the Spring and Autumn Annals, but at some point abandoned his studies and joined the military, eventually becoming the commander of Xiongwu Base (雄武軍, in modern Chengde, Hebei). In 841, during the reign of Emperor Wuzong, the military governor of Lulong, Shi Yuanzhong, was killed in a mutiny. The soldiers initially supported the officer Chen Xingtai () as Shi's replacement, and Chen sent messengers to the imperial capital Chang'an to request commission as military governor. The lead chancellor Li Deyu believed that part of the reason why the three de facto independent circuits north of the Yellow River (Lulong, Chengde (成德, headquartered in modern Shijiazhuang, Hebei), and Weibo (魏博, headquartered in modern Handan, Hebei)) had been so disobedient to the imperial government was that the imperial government had, in the past, been too quick to confirm their military governors, and thus suggested that Emperor Wuzong wait and observe the situation further, to further create uncertainty within the Lulong army. Emperor Wuzong agreed. Soon thereafter, Chen was killed in another mutiny, and the soldiers supported Zhang Jiang () as his replacement. Zhang Jiang also sought an imperial commission, and Emperor Wuzong again failed to act, in accordance with Li Deyu's suggestion. Meanwhile, Zhang Zhongwu sent his subordinate Wu Zhongshu () to Chang'an to submit a petition on his behalf, accusing Zhang Jiang of cruelty and requesting imperial permission to attack Zhang Jiang. When Wu arrived at Chang'an, Emperor Wuzong had the chancellors question Wu further on the situation at Lulong. Wu, under Li