Zheng Su (Chinese:鄭肅),courtesy nameAijing (乂敬), was an official of theChineseTang dynasty, serving as achancellor during the reigns ofEmperor Wuzong andEmperor Xuānzong.
It is not known when Zheng Su is born, and little is known about his ancestry (as his family tree was not listed in the table of thechancellors' family trees in theNew Book of Tang with the other chancellors named Zheng[1]) other than that his family was originally from Yingyang (滎陽, in modernZhengzhou,Henan), and that both his grandfather Zheng Lie (鄭烈) and father Zheng Yue (鄭閱) wereConfucian scholars.[2][3] In 808, Zheng Su passed theimperial examinations in theJinshi class, and further passed a special imperial examination for those good at making rulings. He subsequently served on the staffs of regional governors.[2]
Early inEmperor Wenzong'sTaihe era (827–835), Zheng Su was recalled to the capitalChang'an to serve as a supervisory official at one of the ministries under the executive bureau (尚書省,Shangshu Sheng). In 832, he was made the deputy minister of worship (太常少卿,Taichang Shaoqing). As Zheng was capable in reading ancient texts and knowledgeable about theConfucian classics, it was said that whenever there were disputes among the scholars at the ministry of worship about the meanings of theZuo Zhuan or the three texts about rites (i.e., theRites of Zhou, theEtiquette and Rituals, and theClassic of Rites), Zheng was the one who would settle the disputes.[2]
At that time, Emperor Wenzong favored his oldest sonLi Yong the Prince of Lu and wanted famed Confucian scholars to serve on his staff, so he selected Yu Jingxiu (庾敬休) to serve as Li Yong's teacher, Li Jianfang (李踐方) to serve as Li Yong's military advisor, and Zheng to serve as Li Yong's secretary general, with all three continuing to hold their other posts as well; it was from this point that Zheng began to become well-known. After Li Yong was subsequently createdcrown prince, Zheng was given an additional title as imperial attendant (給事中,Jishizhong).[2] In 834, he, along with his colleague Han Ci (韓佽), made an unsuccessful attempt to stop the promotions Emperor Wenzong was bestowing on the emperor's close associateLi Zhongyan (on account of Li Zhongyan's past crimes).[4] In 835, he was made the deputy minister of justice (刑部侍郎,Xingbu Shilang), and was soon madeShangshu You Cheng (尚書右丞), one of the secretaries general at the executive bureau; he was also put in charge of selecting officials at the ministry of civil service affairs (吏部,Libu).[2]
Early in Emperor Wenzong'sKaicheng era (836–840), Zheng was sent out of Chang'an to serve as the governor (觀察使,Guanchashi) of Shanguo Circuit (陝虢, headquartered in modernSanmenxia,Henan). In 837, he was recalled to Chang'an to serve as the deputy minister of civil service affairs (吏部侍郎,Libu Shilang). As Emperor Wenzong knew that Zheng had previously served under Li Yong and was righteous in his behavior and words, he also made Zheng an advisor to Li Yong and had him teach Li Yong the Confucian classics. Subsequently, when Li Yong began to lose Emperor Wenzong's favor due to accusations made against him by Emperor Wenzong's favoriteconcubineConsort Yang, Emperor Wenzong considered deposing Li Yong. Zheng tried to intercede on Li Yong's behalf by discussing with Emperor Wenzong the Confucian principles on lord-subject and father-son relationships, and Emperor Wenzong thanked him.[2] However, after Li Yong was nearly deposed in 838 and died later that year,[5] Zheng was sent out of Chang'an to serve as the military governor (jiedushi) of Hezhong Circuit (河中, headquartered in modernYuncheng, Shanxi) as well as the mayor of its capital Hezhong Municipality.[2]
After Emperor Wenzong died in 840 and was succeeded by his brotherEmperor Wuzong,[5] it was said that Emperor Wuzong knew that Li Yong had been falsely accused and therefore executed a number of people involved in falsely accusing Li Yong. Meanwhile, the officials at court praised Zheng Su for his faithfulness, so Emperor Wuzong recalled Zheng to serve as the minister of worship (太常卿,Taichang Qing).[2] He subsequently served as the military governor of Shannan East Circuit (山南東道, headquartered in modernXiangfan,Hubei).[3] In 845, he was recalled to serve as actingYou Pushe (右僕射), one of the heads of the executive bureau, and chancellorde facto with the designationTong Zhongshu Menxia Pingzhangshi (同中書門下平章事).[6] He was also put in charge of editing the imperial history.[2]
After Emperor Wuzong died in 846 and was succeeded by his uncleEmperor Xuānzong, Emperor Xuānzong, despising the lead chancellorLi Deyu for his hold on power, removed Li Deyu from his chancellor post and sent him out of Chang'an. As Zheng had a strong friendship with Li Deyu, Zheng was also removed.[2] He was sent to Jingnan Circuit (荊南, headquartered in modernJingzhou,Hubei) to serve as its military governor, continuing to carry theTong Zhongshu Menxia Pingzhangshi title as an honorary title.[6] When he died, he was given posthumous honors, including theposthumous nameWenjian (文簡, "civil and approachable"); his year of death was not recorded in history.[3]