AD 82 1 (the first year of Tang Muzong Changqing; In the seventh year of Tubo Yitai, both the Tang Dynasty and Tubo sent envoys, who first took the oath in Chang 'an, the capital of the Tang Dynasty. The following year, they met again in Tubo Rogge (Lhasa). In 823 AD, the Mongolian language was carved into a stone to erect a monument, and compared with the Sino-Tibetan language, it was planted in front of the Jokhang Temple in Lhasa. That is, the famous nephew league monument in history, also known as Tang Fan League monument or Changqing League monument. It is the unity of the two major ethnic groups, Han and Tibetan.

Friendly historical testimony.