The Tang Dynasty (618–907 CE) is interesting as it was when the Tibetan armies invaded and took over large parts of imperial China.

Wikipedia note:

“The Tang Dynasty (618–907 CE) and the Tibetan Empire (7th–9th centuries CE) maintained a volatile relationship defined by shifting power dynamics. The two empires alternated between periods of brutal military conflict over Silk Road trade routes and peaceful alliances solidified through royal marriages.”

There were 40 decisive battles the Tang empire lost to the Tibetan empire. This is why the areas the Tibetans conquered are still heavily influenced to this day. I have been to China three times and have seen the influence countless times. There are also Tibetan monuments in Beijing for example. There is a long history of imperial wars with the Tibetans leaving their mark on greater China.