How did the Tang Dynasty fall?

It was the Huang Chao uprising leading to the fall of the Tang Empire.

Huang Chao’s army caused tremendous loss but what’s worse shaken the legitimacy of the imperial court. After Huang Chao’s rebellion, many military zones no longer obeyed the order of the imperial court openly. To strike down Huang Chao’s peasant army as well as oppressing those military zones, Tang had to rely more on the Barbarian units to fight as well as granting the official titles to the peasant rebels to “recruit” them.

This created a new phenomenon, different from the past 100 years, which was that while the powerful Tibetan empire in the West exploded and most of the Tang military zones being consumed by the peasant rebel, the new confrontation between the Barbarin faction Shatuo and the “recruited” peasant leader Zhuwen had begun. The two big fishes started to eat small shrimps and expanding themselves.

Among the two, the once peasant rebel and now Tang’s legal General Zhuwen was able to secure the capital and control the Emperor after the political struggle between the Emperor and the eunuch class. He then butchered the entire eunuch class to end this once most powerful political faction for 100 years. Shortly later, he abolished the Emperor and self-claimed the Emperor of the Liang Dynasty.

On the other hand, those loyalists to Tang, therefore, turned to the Barbarian General Li Keyong from the Shatuo faction and whose son Li Cunxu self-claimed the Tang Emperor to inherit the legitimacy of the Tang Empire since their family name Li was officially granted by the previous Tang Emperor. Historians call his dynasty as the late Tang dynasty.

The war between the two didn’t bring the long peace but marked the beginning of the chaotic period of “five dynasties and ten kingdoms”.

Normally, the Tang Dynasty was ended by Zhuwen or no longer existed after the fall of the late Tang Dynasty. Depends on which one you like more.