Zheng Tian (, 821?/825?–883?), courtesy name Taiwen (), formally Duke Wenzhao of Xingyang (), was a Chinese politician and military commander of the late Tang dynasty who served twice as a chancellor under Emperor Xizong, from 874 to 878 and again from 881 to 883, and played a crucial role in the dynasty's resistance to the cataclysmic Huang Chao Rebellion. Zheng was also an accomplished man of letters, and his qijue poem "On Mawei Slope" was included in the Qing-era anthology Three Hundred Tang Poems.
The son of a prominent political figure, Zheng enjoyed early success in the imperial examinations and entered public service at a young age. After his father's political faction fell from favor, he was blacklisted for years and only returned to office in the 860s, after forming an association with the respected statesman Liu Zhan. Zheng secured influential court postings during Liu's brief tenure as chancellor, earning a reputation as a talented edict drafter and military strategist. He remained loyal to Liu when the latter fell from power and was in turn banished from court, but was rehabilitated during the reign of Emperor Xizong and made a chancellor in 874. Although Zheng enjoyed the young emperor's respect, he was marginalized at court by his cousin and fellow chancellor Lu Xie and, following a dispute with Lu, was removed from the chancellorship in 878. Zheng was later appointed as military governor of Fengxiang Circuit, west of the imperial capital of Chang'an. In 881, when Huang Chao's rebel army forced Emperor Xizong to flee to Chengdu, Zheng remained resolutely loyal to the dynasty and was tasked by the emperor with rallying loyalist resistance in the capital region. Relying on his personal wealth, he organized a viable fighting force at Fengxiang Circuit and inflicted a surprise defeat on rebel forces sent to subdue him. Zheng subsequently participated in an unsuccessful military operation to retake the capital and, following a mutiny, rejoined the emperor in Chengdu and was made a chancellor once again. He was forced into retirement in 883, following disputes with the influential court eunuch Tian Lingzi, and died of illness shortly thereafter.
Background and early career
Assuming that Zheng Tian died in 883, he might have been born in either 821 or 825. He was a part of the prominent Zheng clan based in Xingyang (滎陽, in modern Zhengzhou, Henan), but his traceable ancestry only went as far back as his great-grandfather Zheng Shaolin (), who served as a civil service official under the prefect of Zheng Prefecture (鄭州, in modern Zhengzhou). Zheng Shaolin, as well as Zheng Tian's grandfather Zheng Mu () and Zheng Tian's father Zheng Ya (), all passed the imperial examinations in the Jinshi class, and while Zheng Mu served only as a county magistrate, Zheng Ya became well known for his abilities, and he became a close associate of the chancellor Li Deyu, who was particularly powerful during the reign of Emperor Wuzong, eventually serving as a high level imperial consultant. Other than Zheng Tian, Zheng Ya had at least two younger sons, Zheng Jun () and Zheng Pi ().
Zheng Tian himself passed the imperial examinations in the Jinshi class when he was 17, and thereafter served as a staff member under the military governor (Jiedushi) of Xuanwu Circuit (宣武, headquartered in modern Kaifeng, Henan). When he was 21, he further passed a special examination for those who made good rulings, and he was made the sheriff of Weinan County (渭南, in modern Weinan, Shaanxi) and a historian who would edit imperial histories. Before he could serve in those positions, however, in 847, due to his association with Li Deyu, who had lost power during the reign of the then-reigning Emperor Xuānzong (Emperor Wuzong's uncle), Zheng Ya was demoted to be prefect of Gui Prefecture (桂州, in modern Guilin, Guangxi), and Zheng Tian followed his father to Gui Prefecture, where Zheng Ya would die, probably around 849. (This chronology appeared to make it more likely that Zheng Tian was born in 825 or later, as he would have been 22 in 851 if born in 825, whereas he would already be 26 if born in 821.) As, during Emperor Xuānzong's reign, the court scene was dominated by the chancellor Bai Minzhong and then Linghu Tao, both of whom had no liking for Li Deyu and ejected Li Deyu's associates, Zheng Tian was not given an imperial government office for a long time.