The Fragile Return to Chang’an

On December 26, 763, Emperor Daizong (Li Yu) returned to the capital Chang’an after taking refuge in Shaan County during the Tibetan invasion. The scene was charged with tension—General Guo Ziyi led officials and troops to kneel in penitence outside the city gates. The emperor’s weary remark, “Had I employed you earlier, we would not have come to this,” hinted at both regret and the fractured trust between the throne and its military elite.

This homecoming marked a dangerous shift in power dynamics. The eunuch Yu Chao’en, credited with “rescuing” the emperor, entered Chang’an with the elite Shence Army. Appointed as Tianxia Guanjun Rong Xuanwei Chuzhi Shi (Commander of the Imperial Guards), Yu consolidated unprecedented authority. His strategic fortifications at Hu County and Zhongwei Bridge—ostensibly against Tibetan threats—were thinly veiled preparations for the emperor’s next escape route.

Meanwhile, the disgraced general Pugu Huai’en watched from the sidelines, gambling on the court’s collapse. His miscalculation would ignite a chain reaction that tested the Tang’s fragile recovery.

The Unraveling of Pugu Huai’en

Pugu Huai’en, once a celebrated general who helped crush the An Lushan Rebellion, now stood at a crossroads. His relationship with the court had soured over perceived slights and the influence of rival factions like Yu Chao’en. When Guo Ziyi’s miraculous defense of Chang’an dashed Pugu’s hopes of a court surrender, he made a desperate bid for autonomy: seizing Taiyuan to carve out a northern fiefdom allied with the Uyghurs.

This gamble failed spectacularly. Taiyuan’s defender Xin Yunjing uncovered Pugu’s plot, and a botched siege led by Pugu’s son, Pugu Yang, ended in mutiny. On the night of February 764, Pugu Yang was assassinated by his own officers, who defected to Guo Ziyi. The once-loyal Shuo-Fang Army, realizing they’d been deceived about Guo’s death, abandoned Pugu en masse.

A poignant family drama followed. Pugu’s mother, a voice of reason, rebuked him: “I warned you not to rebel! The state treated you well, and now disaster will befall us.” Fleeing with 300 loyalists to Lingwu, Pugu became a rogue warlord—allying with Tibetans and Uyghurs, yet still spared by an emperor who remembered his past service.

The Court’s Delicate Balancing Act

Emperor Daizong’s response to the crisis revealed the Tang’s precarious state. While publicly mourning Pugu’s fall (“I failed to trust a meritorious servant”), he quietly rewarded defectors and honored Pugu’s mother—a gesture that pacified other generals. The emperor’s survival depended on such symbolic acts, as seen with Li Guangbi, another distrustful general who refused to return to court.

Li Guangbi’s death in July 764 marked the end of an era. The “god of war” who stabilized the southeast was given a posthumous Wumu title—a lukewarm recognition of his achievements. His legacy, however, endured: the disciplined armies he trained later formed the backbone of the Shence troops, while his containment of warlords in Henan prevented southern disintegration.

The Economic Lifeline: Liu Yan’s Miracle

Amid military crises, financial wizard Liu Yan emerged as the dynasty’s unsung hero. With the Grand Canal silted and the treasury empty after Tibetan raids, Liu reopened the Bian River waterways in 764, restoring the vital grain supply from Jiangnan. His efforts earned him comparisons to Xiao He, the Han Dynasty’s legendary administrator. This economic reprieve allowed the Tang to limp forward, albeit forever weakened.

The Long Shadow of 763–764

The events of these two winters crystallized the Tang’s new reality:
– Militarized Governance: Regional armies, no longer fully loyal, demanded constant appeasement.
– Eunuch Ascendancy: Figures like Yu Chao’en exploited imperial vulnerability to seize power.
– The Hero’s Burden: Guo Ziyi, now in his 70s, remained the sole figure capable of bridging court and military factions—a role that would soon see him riding alone into Uyghur camps to avert disasters.

As the dust settled, Emperor Daizong issued a general amnesty in February 764—a symbolic fresh start. Yet the Tang’s golden age was irretrievable. The dynasty’s survival now hinged on aging heroes, bureaucratic ingenuity, and the uneasy tolerance of semi-independent warlords. The winter of 763–764 wasn’t just a crisis; it was the blueprint for the Tang’s managed decline.