During the Five Dynasties period, Shi Jingtang rebelled against the Later Tang and sought support from the northern Khitan. The Khitan ruler, Yelü Deguang, personally led his army to crush the Tang forces and installed Shi Jingtang as emperor, establishing the Jin Dynasty. When Shi Jingtang discussed with the Khitan ruler which of his sons should remain in Taiyuan, Yelü Deguang personally selected Shi Chonggui. Yelü Deguang then declared a father-son bond with Shi Jingtang, but this relationship soon ended when the Khitan invaded.
In 942, Emperor Gaozu Shi Jingtang died, and Shi Chonggui ascended the throne, known historically as Emperor Chu. Shi Chonggui was inept at governing, and when severe droughts and locust plagues struck, the people were left destitute, with corpses littering the fields. Empress Dowager Li repeatedly admonished the new emperor, but he ignored her warnings. By the time foreign invaders arrived, the Jin dynasty was already too fragile to resist.
In the spring of 944, the Khitan invaded the Later Jin dynasty. Emperor Shi Chonggui led his forces to resist and sent a letter to Khitan leader Yelu Deguang seeking peace, but was rejected. After repeated battles, the Jin army suffered defeat after defeat. By December, Jin generals Du Wei, Li Shouzhen, and Zhang Yanze had defected to the Khitan. Yelu Deguang dispatched Zhang Yanze with 2,000 elite cavalry to the capital, where they camped outside the Mingde Gate, plunging the city into chaos. Zhang Yanze sent a letter to Empress Dowager Li, stating the Jin army had surrendered, and asked, "One of my maidservants stole a medicine pouch and fled to Jin—are both the person and the pouch still there?" Realizing the dynasty was doomed, the Empress Dowager prepared to burn herself alive alongside the emperor, but the favored minister Xue Chao dissuaded them.
Emperor Chu summoned the scholar Fan Zhi and said to him, "Why has Du Zhongwei betrayed me like this! In the past, when the late emperor raised an army in Taiyuan, he wanted to choose a son to guard Taiyuan. The Khitan emperor favored me. They should know me well. Draft a surrender letter for me, recounting past events, so that perhaps my mother and I may survive."
Fan Zhi drafted the surrender document for the emperor
Fan Zhi drafted a surrender decree for the Empress Dowager, who signed herself "Li, the widow and former empress of the Jin dynasty, your subject." In the memorial, she wrote: "When General Zhang Yanze entered the city, we received your Majesty's letter of comfort. In the past, when the late emperor faced peril, your Majesty personally campaigned to save the Shi family and establish our Jin dynasty. Unfortunately, the late emperor passed away, and his successor failed to govern well, leading to endless wars and this dire outcome. What is done cannot be undone. Now, receiving your Majesty's grace, we feel reborn. I humbly submit this memorial to confess our faults."
Yelu Deguang received the surrender letter from the Emperor and Empress Dowager and replied, "Do not worry; I assure you a place to eat."
When Emperor Yelü Deguang of the Liao Dynasty demoted the Later Jin emperor Shi Chonggui to the rank of Grand Master of Splendid Happiness and titled him "Duke of Broken Faith," he ordered the deposed ruler and his family sent to Huanglong Prefecture. The Liao emperor then sent an envoy to the former emperor's mother, Empress Dowager Li, with a message: "I have heard that Shi Chonggui did not heed your teachings, leading to this downfall. You may seek your own comfort and need not accompany him to Huanglong Prefecture." The empress dowager replied, "Chonggui has always served me with utmost respect. His fault was in defying the will of his late father. Now that he is going to Huanglong Prefecture, fortunate to receive your great mercy and have his life and family spared, if a mother does not follow her son, where else can she go?"
Thus, the Empress Dowager and Empress, along with their entire clan, followed the departing Emperor northward to Huanglong Prefecture.
Later, the idiom "A Team of Four Horses Cannot Overtake" came to be used as a metaphor for irreversible facts that cannot be undone.
Source: *New History of the Five Dynasties*, "Book of Jin", "Biography of Empress Li of Gaozu"
Meaning of the Idiom: Later, the Chinese idiom "驷马难追" came to describe how irreversible facts cannot be undone.