In order to defend the frontier areas, the Tang Dynasty set up jiedushi during the Jingyun period. Initially, this setup existed only in the frontier areas. After the "Anshi Rebellion", the Tang Dynasty set up more emissaries in order to defend the central government.
Temperance makes weight, grasps the local administrative power and military power, and becomes a divided force on the divided side. Jiedu made a post of heir to the post of general, and the Emperor of the Tang Dynasty could only recognize it, turning a blind eye. And these festivals also monopolize local taxes. At this time, the Tang Dynasty became the Zhou Dynasty in the Warring States period.
Between the feudal towns, as well as between the feudal towns and the Tang emperors, there was a constant war in order to seize the population and land. Each clan town supported the army and respected itself, divided one side, and severely threatened the will of the Tang Dynasty. The emperor, on the other hand, was powerless to suppress it.
After the "Anshi Rebellion", the Tang Dynasty established many feudal towns in Hebei, where the "Anshi Rebellion" originated, during which the three towns of Zhaoyi, Chengde and Wei Bo were the most severe, known in history as the "Three Towns of Hebei". They were for a long time opposed to the center of the Tang Dynasty, called "Royal Ministers", and were actually the Tu Emperor.
After Tang Xianzong ascended the throne, he tried to change this situation, used troops against the fanzhen, quelled the rebellion of Wu Yuanji, and also annihilated other fanzhens that did not obey the Tang government, which made the three towns in Hebei, which had always been arbitrary, also have to obey the Tang government, and the country ostensibly restored a unified situation.
But this situation did not last long. In the last years of The Tang Dynasty, in addition to the capital, there were 46 feudal towns in the area under the control of the Tang Dynasty. Most of these towns are independent or semi-independent. However, some important feudal towns related to the security of the Tang Dynasty were controlled by the central government, which ensured the existence of the Tang Dynasty. The division of the town of Fanzhen greatly weakened the control of the Tang central government over the local area.