Unlike most dynasties, the Tang Dynasty advocated opening borders and expanding land. This was particularly evident in the period of Emperor Taizong. The world had just settled, but the Tang Dynasty did not implement the policy of national recuperation, but went directly to war. Emperor Taizong firmly believed that the best defense was attack. At that time, there was a cavalry unit no less than the nomadic people in the Tang Dynasty, which could launch a surprise attack on the Gobi Desert. Therefore, the foreign war in the early Tang Dynasty achieved good results.
The name of our time appeared as early as Tang Gaozong's time. This title refers to the governor who was awarded the diplomatic envoy. They can control all kinds of armies. However, this is not a formal official position. It was not until Tang Ruizong's time that the official status of our Commissioner was officially accepted. Of course, this does not mean that our emissary has replaced the Governor. Until the late Tang dynasty, there was still the post of governor. Therefore, the original intention of setting up a special envoy is to ensure the border security of the Tang Dynasty.
In addition, in order to make the military town resist the rebels, Tang Xuanzong abolished the ambassador and replaced it with our special envoy, which increased the power of our ambassador. When Tang Suzong was in power, the world was not peaceful, so he followed the state grazing system of the Han Dynasty and let us rule the local military and political power in this era. This gives our emissary military, financial, administrative and personnel power. Over time, soldiers are often more loyal to our times than emperors. By the late Tang dynasty, it had obtained hereditary qualification and eventually became the main force that directly threatened the court and even overthrew the Tang dynasty.