家世和早期仕途

鄭從讜出自滎陽鄭氏北祖第二房，祖父鄭餘慶在唐德宗及其孫唐憲宗年間為宰相，父親鄭澣雖然未曾拜相，長期任朝廷官員，于開成四年（839年）卒于山南西道節度使任上，享年六十四歲。鄭從讜有三兄鄭允謨、鄭處誨、鄭茂休，都是朝廷官員。他的三重堂弟鄭延昌後來也成為宰相。

鄭從讜于唐武宗會昌二年（842年）中進士，初任校書郎，歷任拾遺、補闕、尚書郎、知制誥。宰相令狐綯、魏扶都是鄭澣主持科舉時的門生，出于感激而張揚鄭從讜的聲譽，鄭從讜被提拔為中書舍人。

唐懿宗年間

唐懿宗咸通三年（862年），鄭從讜任禮部侍郎，知貢舉，又轉刑部，又改吏部。六年（865年）二月，考宏詞選人。他選拔官員得當，眼看即將拜相，但因拒絕權臣請託，七年（866年）三月被出為檢校刑部尚書、兼太原尹、北都留守、御史大夫、上柱國、滎陽縣開國男、食邑三百戶，充河東節度管內觀察處置等使。任職一年有餘後，他請求回京，未獲准，十一年（870年）十一月改檢校戶部尚書，兼汴州刺史、御史大夫，充宣武軍節度使。因兄鄭處誨卒于宣武軍節度使任上，他不于公署舉樂，友悌知禮操履如此。他管治宣武時政聲良好，當權者怕他被提升，十二年（871年）十二月，他被調任廣州刺史、嶺南東道節度觀察處置等使。在廣州期間，他幾無可用的軍隊，北面也無援軍，卻要應對南詔蠻的侵擾。他招募獠人土豪，任以軍務，因而儘管叛軍人多勢眾，廣州也得以安定。

唐僖宗年間

第一次拜相前

十四年（873年），唐懿宗崩，子唐僖宗繼位。鄭從讜不想再呆在嶺南，屢次上表，寧可在東都洛陽保有榮銜任散職。乾符元年（874年）五月，僖宗召他回長安，由嶺南東道節度使、檢校刑部尚書改任為刑部尚書。四年（877年）正月和五年（878年）三月，再考宏詞選人。九月，鄭從讜在吏部尚書任上被任為中書侍郎，授同中書門下平章事，為實質宰相。

第一次拜相

鄭從讜第一次拜相任內的作為沒有太多記載。當時，河東屢為兵變所苦，還有被沙陀都督李國昌及其子李克用率領的叛軍攻打的危險。廣明元年（880年）二月，節度使康傳圭死于兵變，朝廷決定讓宰相鎮守，任當時被稱為「開府儀同三司、門下侍郎、兼兵部尚書、充太清宮使、弘文館大學士、延資庫使、上柱國、滎陽郡開國公、食邑二千戶」的鄭從讜為檢校司徒、同平章事，兼太原尹、充北都留守河東節度、管內觀察處置兼代北行營招討供軍等使，允許他自己選擇參佐。鄭從讜因而奏請很多名士為幕僚，奏長安令王調為副使，兵部員外郎、史館修撰劉崇龜為節度判官、度支判官、檢校吏部郎中、御史中丞，前司勛員外郎、史館修撰趙崇為觀察判官，前進士劉崇魯充推官，前左拾遺李渥充掌書記，前長安尉崔澤充支使，他的幕府因而被稱為「小朝廷」。

拜相間隙

回到河東的鄭從讜外表溫和，實則多謀善斷，能覺察兵變計劃並誅殺謀劃者，並安撫餘眾。如舊府城都虞候張彥球為同僚所迫參與了殺死康傳圭的兵變，鄭從讜不但安撫他，還委他以軍權，遂得其效死力。

十二月，長安受到農民大軍黃巢進攻的威脅，僖宗差供奉官劉全及慰諭鄭從讜，鄭從讜奉詔遣牙將論安、後院軍使朱玫率步騎五千隨夏綏節度使諸葛爽南下盡力協助保衛都城，但未及相助，長安已陷落。論安率師入關至陰地，帶著數百士兵擅歸，鄭從讜集諸部校斬之于鞠場，再將兵眾交給朱玫勤王。黃巢奪取帝位，稱大齊皇帝，但鄭從讜和其他唐將繼續抵抗。中和元年（881年），鄭從讜被加侍中、行營招討使，五月，李克用稱幫助朝廷，募達靼萬人趨代州，請求鄭從讜讓他南下行過河東。鄭從讜除了給李克用糧料和錢千貫、米千石外，拒絕補給他的軍隊，塞石嶺關，李克用不得前，抄近路到太原，營于城下五日，索要糧貲，鄭從讜不答，李克用大掠，還屯代州。鄭從讜遣大將王蟾、薛威出師追擊，並求援于振武節度使契苾璋；契苾璋率突厥和吐谷渾軍隊來援，李克用北撤，又攻取忻州。

中和二年（882年），契苾璋得到當時在成都的唐僖宗授權，攻打李克用，僖宗還命鄭從讜協助。十月，嵐州刺史湯群因倚仗沙陀，被朝廷懷疑，調為懷州刺史，鄭從讜遣人將官告授湯群，湯群怒，殺使者，據城，接納沙陀人。鄭從讜遣張彥球率兵討之。但同月，討黃巢軍的行營都監楊複光說服朝廷徵募沙陀以擊敗黃巢。諸道行營都統宰相王鐸以僖宗名義赦免並召李克用加入朝廷軍，並下令鄭從讜勿幹涉。李克用率軍南下時，仍命軍隊繞開太原，親自與數百騎去太原向鄭從讜道別。鄭從讜也不肯借道，李克用軍挨著太原紮營，跟隨的數騎喊道：「我們要西行了，要和公說句話。」以幣馬給鄭從讜，鄭從讜登城慰勉，也以名馬、器幣、糧食、軍器相贈。李克用隨後繼續南下加入朝廷軍對抗黃巢。

中和三年（883年）三月唐軍在李克用的貢獻相助下收複長安後，李克用短暫回到代州，但很快僖宗下詔褒獎他，五月任為河東節度使，鄭從讜奉詔，將河東讓給李克用。鄭從讜被改任東都留守、檢校司空兼侍中，同月又被任為司空、門下侍郎，再授同中書門下平章事，為宰相。行經絳州，依附刺史唐彥謙，留駐數月。七月，奉召到行在。

鄭從讜與同宗鳳翔節度使鄭畋被黃巢軍稱為「二鄭」，唐朝得以複振也是這兩位儒帥之功。

第二次拜相與過世

之前張彥球守城有功，得鄭從讜累奏為行軍司馬，鄭從讜再度拜相後，用為金吾將軍，累任郡刺史。先前鄭從讜在絳州時，唐彥謙判官陸扆嗜學有才思，鄭從讜每天與之談宴無間，于是在朝上稱讚他，使之位至高官。

曾改任司徒。光啟二年（886年）二月，鄭從讜被加侍中、守太傅。光啟三年（887年）三月，請辭，改太子太保，當時並無皇太子，故完全只是榮銜。他不久去世。謚文忠。

子孫

子鄭璘，字華聖。

注釋及參考文獻

Background and early career

It is not known when Zheng Congdang was born. His family claimed ancestry from the ruling house of the Spring and Autumn period state Zheng, and his grandfather Zheng Yuqing served as a chancellor during the reigns of Emperor Dezong and Emperor Dezong's grandson Emperor Xianzong. Zheng Congdang's father Zheng Guan (鄭澣) was himself a long-time imperial official, although he was never chancellor, dying while serving as the military governor (Jiedushi) of Shannan West Circuit (山南西道, headquartered in modern Hanzhong, Shaanxi) in 839 at the age of 63. Zheng Congdang had three older brothers, Zheng Yunmo (鄭允謨), Zheng Maoxiu (鄭茂休), and Zheng Chuhui (鄭處誨), each of whom served in the imperial government as well. (A third cousin, Zheng Yanchang, would be a future chancellor.)

Zheng Congdang himself passed the imperial examinations in the Jinshi class in 842, during the reign of Emperor Xianzong's grandson Emperor Wuzong. He started as his governmental career as a copyeditor (校書郎) at the Palace Library, and thereafter served as an advisory official, and then a supervisory official at the executive bureau of government (尚書省, Shangshu Sheng), eventually becoming responsible for drafting edicts. As the chancellors Linghu Tao and Wei Fu both passed the imperial examinations while Zheng Guan oversaw the imperial examinations, they both felt indebted to Zheng Congdang and thus enhanced Zheng Congdang's reputation. As a result, Zheng was subsequently promoted to Zhongshu Sheren (中書舍人), a mid-level official at the legislative bureau (中書省, Zhongshu Sheng).

During Emperor Yizongs reign

In 862, by which time Emperor Wuzong's cousin Emperor Yizong was emperor, Zheng Congdang was made deputy minister of rites (禮部侍郎, Lǐbu Shilang) and put in charge of the imperial examinations. He was later made deputy minister of justice (刑部侍郎, Xingbu Shilang) and then deputy minister of civil service affairs (吏部侍郎, Lìbu Shilang, note different tone). It was said that he selected appropriate officials while overseeing the civil service, but that, as a result of refusing to bow to powerful individuals' wishes, was sent out of the capital to serve as the military governor of Hedong Circuit (河東, headquartered in modern Taiyuan, Shanxi) as well as the mayor of its capital Taiyuan Municipality. After he served there for a year, he requested a return to the capital, but the request was not accepted; rather, he was transferred to Xuanwu Circuit (宣武, headquartered in modern Kaifeng, Henan) to serve as its military governor and the prefect of its capital Bian Prefecture (汴州). He was said to have governed Xuanwu well, causing the powerful individuals at that time to be apprehensive that he would be promoted. He was thus transferred to Lingnan East Circuit (嶺南東道, headquartered in modern Guangzhou, Guangdong) to serve as its military governor and the prefect of its capital Guang Prefecture (廣州). While at Guang Prefecture, he had to dealt with many incursions and non-Han rebellions with few troops available to him and no reinforcements from the north, but he managed the situation by commissioning non-Han tribal chiefs to deal with the military matters. It was said that despite the large number of rebellions, Guang Prefecture was safe.

During Emperor Xizongs reign

Prior to first chancellorship

Emperor Yizong died in 873 and was succeeded by his young son Emperor Xizong. Zheng Congdang, who did not want to remain in Lingnan East longer, submitted repeated petitions, offering even to accept an honorary position at the eastern capital Luoyang. Emperor Xizong then recalled him to Chang'an to serve as minister of justice (刑部尚書, Xingbu Shangshu). In 878, when Zheng was referred to at the minister of civil service affairs (吏部尚書, Lìbu Shangshu), he was made Zhongshu Shilang (中書侍郎), the deputy head of the legislative bureau, and given the designation Tong Zhongshu Menxia Pingzhangshi (同中書門下平章事), making him a chancellor de facto.

First chancellorship

Not much was recorded about Zheng Congdang's acts as chancellor in his first term. At this time, Hedong Circuit had been plagued by repeated mutinies, as well as the danger of being attacked by Shatuo rebels led by the chieftain Li Guochang and Li Guochang's son Li Keyong. After a mutiny in 880 led to the death of the military governor Kang Chuangui (康傳圭), the imperial government decided that it would take someone as senior as a chancellor to deal with the situation, so Zheng was commissioned as the military governor of Hedong and allowed to select his own staff members. Zheng thus invited many well-known individuals to serve on his staff, and his staff was described as a miniature imperial government. He retained the Tong Zhongshu Menxia Pingzhangshi title as an honorary title.

Between the chancellorships

Back at Hedong, Zheng Congdang was described as apparently mild in disposition, but was full of strategies and decisive. He was able to discover mutiny plots well, and he executed those who planned mutinies, while comforting the rest. For example, the officer Zhang Yanqiu (張彥球), who was forced by his colleagues to participate in the mutiny that killed Kang Chuangui, was someone that Zheng comforted and entrusted with military commands.

In late 880, with Chang'an under the threat of attack by the major agrarian rebel Huang Chao, Zheng was ordered to transfer his soldiers to Zhuge Shuang and Zhu Mei and have Zhuge and Zhu head south to try to help defend the capital, although the capital fell apparently before Zhuge and Zhu could actually do so. Huang took the throne as the emperor of a new state of Qi, but Zheng, along with other Tang generals, continued resisting. Meanwhile, in 881, Li Keyong, claiming that he was coming to the imperial government's aid, requested that Zheng allow him transit through Hedong. Zheng did not refuse, but declined to supply his troops (besides giving Li Keyong a small amount of food) and prepared for a siege of Taiyuan, causing Li Keyong to respond by pillaging Hedong Circuit. Zheng sought aid from Qibi Zhang (契苾璋) the military governor of Zhenwu Circuit (振武, headquartered in modern Hohhot, Inner Mongolia); Qibi came to his aid with ethnic Tujue and Tuyuhun troops, and Li Keyong withdrew north, capturing Xin (忻州, in modern Xinzhou, Shanxi) and Dai (代州, also in modern Xinzhou) Prefectures.

In 882, Qibi Zhang received imperial permission (from Emperor Xizong, who was then at Chengdu) to attack Li Keyong, and Emperor Xizong further ordered Zheng to assist Qibi. However, by winter 882, the eunuch monitor of the armies against Huang, Yang Fuguang, had convinced the imperial government that it was necessary to enlist the Shatuo to defeat Huang. The chancellor in charge of the operations against Huang, Wang Duo, thus issued an edict in Emperor Xizong's name pardoning and summoning Li Keyong to the imperial cause, and further ordering Zheng not to interfere. Still, as Li Keyong was leading his troops south, he instructed his troops to avoid Taiyuan, but personally went to Taiyuan to greet Zheng. Zheng gave him a gift of horses and treasures. Li Keyong then continued south to join the imperial cause against Huang.

After the Tang forces recaptured Chang'an in spring 883—a battle in which Li Keyong's contribution was instrumental—Li Keyong returned to Dai Prefecture briefly, but soon, Emperor Xizong issued an edict to reward Li Keyong by making him the military governor of Hedong, while summoning Zheng to Emperor Xizong's presence. Zheng accepted the edict and yielded Hedong to Li Keyong. Zheng was then made Sikong (司空), one of the Three Excellencies, as well as Menxia Shilang (門下侍郎), the deputy head of the examination bureau (門下省, Menxia Sheng), as well as chancellor again with the designation Tong Zhongshu Menxia Pingzhangshi.

Second chancellorship and death

Not much was recorded about Zheng Congdang's acts as chancellor in his second term. In 886, he was given the greater chancellor title of Shizhong (侍中, i.e., the head of the examination bureau), as well as Taifu (太傅). In 887, he offered to retire, and he was made a senior advisor to the Crown Prince—an entirely honorary title since there was no crown prince at the time. He died soon thereafter. He was given the posthumous name Wenzhong (文忠, "civil and faithful").

Notes and references

• Old Book of Tang, vol. 158.

• New Book of Tang, vol. 165.

• Zizhi Tongjian, vols. 253, 254, 255, 256.