Zheng Yin (鄭絪) (752 – December 3, 829[1][2]), courtesy name Wenming (文明), was a Chinese historian and politician during the Tang dynasty, serving as a chancellor during the reign of Emperor Xianzong.
[a] Zheng was later recalled to the central government to initially serve as Bujue (補闕), a low-level consultant, as well as Qiju Lang (起居郎), a chronicler of the emperor's acts; he was also involved in editing the imperial history.
[3] In 796, there was an occasion when Emperor Dezong, when commissioning eunuch commandants of the imperial Shence Army (神策軍), Dou Wenchang (竇文場) and Huo Xianming (霍仙鳴), was set to issue edicts on hemp paper, when Zheng objected – pointing out that traditionally, only the creation of imperial princes and the commissioning of chancellors involved the use of edicts on hemp paper and questioning whether this would set a dangerous precedent of equating commandants of the Shence Army with such honored individuals.
The next day, Emperor Dezong told Zheng, "Not even the chancellors dared to resist the eunuchs' requests, and I did not realize this until you brought this up.
[6] During Emperor Shunzong's brief reign, his close associates Wang Shuwen and Wang Pi, his concubine Consort Niu, and the eunuch Li Zhongyan (李忠言), formed a group of decision-makers, as Emperor Shunzong was unable to speak and himself unable to rule on important matters.
[6] Later, after Li Chun was named regent, Zheng continued to be imperial scholar but also received the office of Zhongshu Sheren (中書舍人), of a mid-level official at the legislative bureau.
[6] It was said, however, that at the time fellow chancellor Du Huangchang, who was advising Emperor Xianzong on reforms, especially the wresting of control back from regional warlords, made most of the decisions, and that Zheng was often silent.
Yet later, he served as the prefect of Tong Prefecture (同州, in modern Weinan, Shaanxi) as well as the director of Changchun Palace (長春宮).
He was then recalled to be the minister of defense (兵部尚書, Bingbu Shangshu) but soon thereafter made the military governor of Hezhong Circuit (河中, headquartered in modern Yuncheng, Shanxi).