Looking at China's history, it is not difficult for us to find that in the period of the power of a dynasty, the centralization of power must be unprecedentedly strengthened. The so-called centralized power means that the local government has no independence in the political, economic, military and other aspects, and must strictly obey the orders of the imperial court. However, when a dynasty declines, there is bound to be a situation of local division, making the imperial court powerless to eliminate the division, and eventually, leading to its demise.
The Tang Dynasty, on the other hand, was in this situation.
People often say: "Han died in foreign relations, Tang died in Fanzhen, Song died in foreign enemies, and Ming died in party struggle." The demise of the Tang Dynasty was due to the division of the feudal towns, so how did the feudal towns come about?
This matter has to start from the late stage of the Anshi Rebellion. In 763 AD, with the suicide of Shi Chaoyi, after nearly eight years, after the Anshi Rebellion of the three generations of emperors of the Tang Dynasty, it finally came to an end, ending with the victory of the Tang Dynasty. Although the war was basically calmed, it was difficult for the Tang Dynasty to return to its heyday. The recovery after the war and the resettlement of the rebel party have become major problems that the imperial court urgently needs to solve after that.
The suppression of the rebellion also exhausted the strength of the troops, leaving the Tang court in a state of "weakness" after the war. However, the misfortune is not alone, and Tubo has also tried to take a piece of the pie and repeatedly launched attacks. Unable to gather more troops, datang could only choose to surrender the Anshi rebels, and made Three of Shi Chaoyi's generals Zhang Zhongzhi, Li Huaixian, and Tian Chengsi the envoys of the Chengde Army, Lulong Jiedushi of Youzhou, and Wuzhou.
Since then, the rebels have been entrenched in the "Three Towns of Heshuo" for more than a hundred years, and also opened up the situation of the division of the town and the "Chang'an Tianzi and Wei Fuya Army".
The "three towns of Heshuo" had apparently submitted to it, but in fact, they did not obey the governance of the Tang court, and they repeatedly rebelled.
Since Emperor Daizong, successive emperors of the Tang Dynasty have launched attacks against the "Three Towns of Heshuo", but they have never been able to uproot it. Until the fall of the Tang Dynasty, the situation of the division of the feudal towns still existed. In the past, the most fierce rebellion of the "Three Towns of Heshuo" was during the reign of Emperor Dezong of Tang, and even a farce of "claiming the king" was staged here.
By 781, Li Baochen (張志忠, renamed Li Baochen after the surrender of Tianzi), Tian Chengsi, and others who had been summoned by the imperial court had died one after another. After Li Baochen's death, his son Li Weiyue wrote to him for succession, but was rejected by Emperor Dezong of Tang. This incident became the fuse for the rebellion of the fan town, causing Li Weiyue to disobey the alliance with Li Zhengji, Liang Chongyi and others.
At this time, the imperial court took the lead in sending Li Xilie to suppress it, and Liang Chongyi committed suicide in August. The following year, Wang Wujun killed Li Weiyue and surrendered to the imperial court, but because he was dissatisfied with the reward issued by the imperial court, he once again colluded with Zhu Tao and others to rebel, and after that, he even claimed to be the king. As a result, the war further expanded to a situation that the imperial court could not control, and finally ended with Tang Dezong's edict.
Of course, there were also times when the imperial court overpowered the "three towns of Heshuo".
During the reign of Emperor Xianzong of Tang, after Wang Chengzong's death, his brother Wang Chengyuan returned to the court, Li Shidao was suppressed, and Tian Hongzheng was reversed, contributing to the short-lived "Yuan and Zhongxing". However, after the death of Tang Xianzong, the strength of the Tang Dynasty was not enough to deter the soldiers and civilians of the fanzhen, and the "three towns of Heshuo" immediately returned to their old state and wandered away from the edge of the imperial court's jurisdiction.
After the central government took over Heshuo, due to the arrogance of the governors, Lu Long, Wei Bo, and Cheng De rebelled one after another, causing the Tang to fall into the predicament of the feudal town again. For more than a hundred years, it has become a common practice for the "Three Towns of Heshuo" to establish a festival commander on their own, and there have been fifty-seven festival envoys in the past, but the festival marshals appointed by the imperial court are only four.
So, why did the "Three Towns of Heshuo" become the biggest problem of the Tang Dynasty?
The "Three Towns of Heshuo" is located in the area north of the Yellow River, with a highly developed economy, and the emblem tax occupies half of Kyushu, and Jizhou is rich in war horses. These financial and material resources provide the primary material basis for armed division. Moreover, this area has long belonged to the frontier area of the country, so the soldiers and civilians are physically strong and have strong combat effectiveness. These conditions laid the military foundation for the "three towns of Heshuo."
Not only that, the three clan towns belong to different leaders, and they are usually in a state of self-care, and occasionally there will be friction and fighting. However, they were both from the Anshi rebel army, and their lips and teeth were cold, and they faced the imperial court with the attitude of mutual hatred and confrontation after all. Once the imperial court had the idea of liquidating them, they would hold on to the group and the coalition would resist together. Therefore, the strength of the "Three Towns of Heshuo" is one of the reasons why it can always exist.
In addition, as early as before the outbreak of the Anshi Rebellion, with the rapid development of the Tang Dynasty's economy, the economy of the small peasants under the equalized field system had been destroyed, which caused a large number of ordinary people to lose production, and at the same time, accompanied by a sharp reduction in the army, the class contradictions were sharpened to a critical point. Although the officials of the imperial court discovered this problem, they have not been able to find a solution, which makes these hidden dangers hidden in the prosperous world always exist.
Eventually, after the Anshi Rebellion, a full-blown outbreak broke out. The Tang Dynasty regained the lost land and recaptured the world, but it faced the intrusion of Tubo that "smelled the smell". After that, the imperial court surrendered the "three towns of Heshuo", and while they confronted foreign enemies, they were not under the control of the imperial court, and even repeatedly launched turmoil. In the more than one hundred years of the middle and late Tang Dynasties, the imperial court had to deal with foreign enemies and be vigilant against the resistance of the "three towns of Heshuo", and there was no opportunity to resume production with all its strength.
Just imagine, the country has no economic foundation, how to calm the chaos, development, so that the imperial court can only carefully maintain the balance between the few. In this case, as Emperor Wenzong's chancellor Niu Zengru said: the rebellion of the feudal towns to the imperial court was no longer the focus, but whether they could resist foreign enemies in the north.
From the Anshi Rebellion to the fall of the Tang Dynasty, it lasted for more than 150 years. Over the years, the "Three Towns of Heshuo" has always been a headache for the imperial court, and it is also one of the important reasons for the demise of the Tang Dynasty.
Resources:
[New Book of Tang?] Lectionary 135? Fanzhen Wei Bo", "Study on the Problem of Fanzhen in the Tang Dynasty", "Old Book of Tang, Vol. XIII, Benji XIII"]