Historical Analysis: The Emperor Taizong of Yuan Was Not a Protagonist in the Xu Zizhi Tongjian

Brief Introduction

The Emperor Taizong of Yuan, named Yisun, was formally known as Yusitemuur (Yisohtemur). He was the fourth emperor of the Yuan Dynasty. He was the eldest son of Emperor Wu (Xianzong) and the grandson of Emperor Renzong (Yuzong). The Emperor Taizong reigned for only two years (1323–1328). During his rule, internal political struggles within the Yuan Dynasty were intense due to the "Southern Curtain Incident" and questions of imperial succession. He ultimately died at Shangdu, allegedly from poisoning or natural causes, which triggered the subsequent accession of Emperor Shunzong and a power shift involving the political elite.

However, it is crucial to clarify a key historical fact: *the Xu Zizhi Tongjian (Continued Comprehensive Mirror for Aid in Governance) does not contain records of the Emperor Taizong. The Xu Zizhi Tongjian was commissioned by the Qianlong Emperor of the Qing Dynasty and officially compiled in the 1780s. Its primary content covers the history of the Southern Song and Jin dynasties (1126–1279). In contrast, the history of the Yuan Dynasty, to which the Emperor Taizong belonged, began when the state name was changed to "Great Yuan" in 1271, with its main events concentrated in the 14th century. Therefore, records of the Emperor Taizong’s life are primarily found in the Yuan Shi (History of Yuan), particularly the "Biography of the Emperor Taizong" and in Mongol-period sources such as the Huigu Leixi Biao (An Outline of the History of the Khotai/Black Tartars), rather than in the Xu Zizhi Tongjian*.

Core Knowledge Points

1. Identity and Lineage:
* The Emperor Taizong, Yisun, was a direct descendant of Ögedei, the second son of Genghis Khan.
* He was the son of Emperor Wu of Yuan (Kaidu, known as Hushan) and the cousin of Emperor Renzong of Yuan (Ayurbarwada, known as Yuzong).
* In 1323, prior to the eventual accession of Emperor Yingzong (also known as Shunzong), Yisun was first enthroned as emperor and is historically referred to as Emperor Taizong.

2. The "Southern Curtain Incident" and Imperial Succession:
* In the early period of his reign, Emperor Taizong attempted to continue the governance policies of his father, Emperor Wu.
* In 1328, Emperor Taizong and the heir (later Emperor Shunzong) were on the same boat on the Hou Lake (Back Lake). Shunzong fell into the water, and Emperor Taizong allegedly refused to save him (some accounts suggest poisoning), resulting in Shunzong’s survival and Emperor Taizong’s death shortly thereafter.
* After Emperor Shunzong ascended the throne, he launched the "Southern Curtain Incident" to purge the old factions associated with Emperor Taizong, thereby consolidating his own power.

3. Historical Positioning:
* Emperor Taizong’s reign was extremely short, and his policies largely followed those of his predecessors, with no major reforms.
* There is controversy surrounding the cause of his death, which served as a pivotal node in the escalation of internal strife during the mid-Yuan period.

Connection to the Xu Zizhi Tongjian and Yuan Dynasty Historiography

Although the Emperor Taizong is not within the scope of the Xu Zizhi Tongjian, understanding this "displacement" has significant value for historical popularization:

1. Boundaries of Dynastic Histories: The Xu Zizhi Tongjian ends at the fall of the Song Dynasty. The history of the Yuan Dynasty is recorded in specialized works such as the Yuan Shi (officially compiled by the Ming Dynasty) or the Menggu'er Shi Ji (History of the Mongols, written by Ke Shaomin during the Republic era). When researching Yuan emperors, the Yuan Shi should be the reference.
2. Sources of Confusion: Some online resources may misinterpret the character "Xu" (Continued) as "continuing into the Yuan Dynasty." In reality, the "Xu" in Xu Zizhi Tongjian means it is a continuation of the Zizhi Tongjian (which ended at the Five Dynasties), and the Xu Zizhi Tongjian itself stops at the end of the Song Dynasty.
3. Correct Historical Sources: To study the Emperor Taizong, one should consult Yuan Shi, Volume 23, Basic Records 23, or the New Yuan Shi (written by Tu Ji during the Republic era), rather than the Qing-dynasty compilation of Song and Jin dynastic history, the Xu Zizhi Tongjian.

Conclusion

The Emperor Taizong, Yisun, was a brief but pivotal monarch of the Yuan Dynasty, whose life profoundly influenced the power structure of the mid-Yuan period. However, it must be noted that he was not a subject of record in the Xu Zizhi Tongjian. Accurate historical research should point to specialized historical texts such as the Yuan Shi, reflecting the importance of "dynastic boundaries" and "source correspondence" in historical literature.