Tang Xuanzong Li Longji: The Rise and Fall in Zizhi Tongjian

Brief Introduction

Tang Xuanzong Li Longji (685–762) was the seventh emperor of the Tang Dynasty, with the temple name Xuanzong. He was the son of Emperor Ruizong Li Dan. Initially enfeoffed as the Duke of Chu, he was later established as Crown Prince and ultimately ascended the throne. Li Longji's life represents a pivotal chapter in Chinese history: in the early period, he initiated the "Kaiyuan Prosperity," bringing the Tang Dynasty's national strength to its peak; in the later period, the outbreak of the "An Lushan Rebellion" led the empire from prosperity into decline. He reigned for 44 years, making him one of the longest-reigning emperors in Chinese history.

Core Knowledge Points

* Rise to Power: Li Longji eliminated the faction of Empress Wei through the "Tanglong Coup," assisted his father, Emperor Ruizong, in restoring the throne, and subsequently ascended the throne himself, demonstrating exceptional political acumen.
* Kaiyuan Prosperity: In the early years of his reign, he governed with diligence and integrity. He appointed capable ministers such as Yao Chong and Song Jing, reformed the bureaucracy, and developed the economy, resulting in a prosperous society.
* Tianbao Crisis: In his later years, he became negligent in governance, favored Li Linfu and Yang Guozhong, and indulged An Lushan's accumulation of military power. This led to corruption in court politics and a loss of control over border defenses.
An Lushan Rebellion: In 755, An Lushan rebelled. War engulfed the north, forcing Xuanzong to flee to Shu. He eventually abdicated to become the Retired Emperor (Taishang Huang*), and the Tang Dynasty entered a period of warlordism dominated by regional military governors.

Connection with Zizhi Tongjian

As a chronological general history, Zizhi Tongjian records Tang Xuanzong with significant warning implications. Sima Guang did not simply judge in the book; instead, through detailed historical records, he revealed the internal logic of "decline following peak prosperity."

1. Records on Personnel Decisions: The book focuses on the turning point where Xuanzong relied on wise ministers in the early period, but later dismissed Zhang Jiuling and placed heavy reliance on Li Linfu. Sima Guang pointed out that in his later years, Xuanzong "loved grand achievements and trusted traitors," leading to the decline of the path of the virtuous and the rise of the path of the petty. This was the key to the turning of national fortune.
2. Warning on Vigilance in Peace: Zizhi Tongjian uses the case of Xuanzong's later indulgence in pleasure and neglect of border defense to illustrate the principle that "prosperity leads to complacency, while adversity breeds caution." The book details how Xuanzong transformed from a diligent ruler to a negligent one, providing a lesson for future rulers to "learn from the past to aid in governance."
3. Depth of Historical Evaluation: In the commentary sections known as "The Historian Says" (Chen Guang Yue), Sima Guang's evaluation of Xuanzong is complex and profound. He affirmed Xuanzong's early achievements but emphasized his later faults more strongly, believing that an emperor's virtue and decisions directly determine the rise and fall of the nation.

Conclusion

In summary, the life of Tang Xuanzong Li Longji in Zizhi Tongjian is not merely an imperial biography, but a warning record on statecraft and governance. By studying the relevant content in the book, we can gain a deeper understanding of historical cycles and understand the truth that "maintaining success is more difficult than creating it."