The Physician Behind the Powerful Eunuchs of the Tang Dynasty: Zheng Zhu and the Political Storms in Zizhi Tongjian

Brief Introduction

Zheng Zhu (?–835) was a highly controversial historical figure in the late Tang Dynasty. Originally a medical official in the Imperial Medical Bureau, he leveraged his exceptional medical skills to befriend Wang Shoucheng, the leader of the eunuchs, and subsequently gained the trust of Emperor Wenzong, rapidly rising to the core of power. In the records of Zizhi Tongjian (Comprehensive Mirror in Aid of Governance), Zheng Zhu was not merely a physician; he was also appointed as the Military Commissioner (Jiedushi) of the Zhaoyi Army (involving the authority of the Zhaoyi Military Secretary). He was a key pawn in Emperor Wenzong's attempt to eliminate eunuch power and restore imperial authority. The ups and downs of his fate profoundly reflect the political turmoil of the late Tang and the decline of imperial power.

Core Knowledge Points

1. Medical Background and Eunuch Network: Zheng Zhu was not from a traditional aristocratic family but started his career through medicine. By curing Wang Shoucheng's chronic illness, he established a deep personal relationship, which became his stepping stone into the political arena.
2. Appointment as Military Commissioner of the Zhaoyi Army: The Zhaoyi Army was stationed in Ze-Lu, a strategic stronghold of the Hebei regional governors. Before planning the coup, Emperor Wenzong appointed Zheng Zhu as the Military Commissioner of the Zhaoyi Army, intending for him to control military power to counter the eunuchs. This appointment marked his transition from a court physician to a regional military and political leader. Although nominally a Military Commissioner, he initially operated with titles such as Military Secretary.
3. Li-Zheng Alliance and the Sweet Dew Incident: Zheng Zhu allied with Prime Minister Li Xun to conspire against the eunuchs. However, due to poor planning, the "Sweet Dew Incident" failed in 835. Zheng Zhu was intercepted and killed by the eunuch Qiu Shiliang en route.
4. Historical Positioning: He was a tragic figure under the lingering glow of the "Revival of Yuanhe." His failure marked the complete defeat of the imperial power's struggle against the eunuchs.

Connection with Zizhi Tongjian Content

The records of Zheng Zhu in the Tang Annals section of Zizhi Tongjian are extremely detailed. Sima Guang demonstrated Zheng Zhu's talents and limitations through objective narration. The book particularly emphasized the background of Zheng Zhu's appointment as Military Commissioner of the Zhaoyi Army: this was Emperor Wenzong's attempt to balance eunuch power by trying to support new regional governor forces. However, Sima Guang also implied that Zheng Zhu lacked support from the scholar-official community, and many court officials viewed him as a mere court favorite.

In the context of Zizhi Tongjian, Zheng Zhu's story is not just a personal biography but a microcosm of the late Tang political ecology. Sima Guang used this case to warn future rulers: governing a country should not rely on intrigue and close attendants. If someone with a medical background is given control over military power, it may balance powers temporarily, but it is difficult to establish a solid foundation. Zheng Zhu's death announced the collapse of Emperor Wenzong's political ideals, and the Tang Dynasty subsequently fell into deeper eunuch dominance and regional fragmentation.

Conclusion

Zheng Zhu's brief career, from medical official to commander of the Zhaoyi Army, serves as an important footnote to the political decline of the late Tang in Zizhi Tongjian. His rise and fall revealed the powerlessness of imperial power caught between eunuchs and regional governors, providing a valuable warning for future generations to understand Tang history.