The most precious place in the Mogao Grottoes is actually not the thousands of sculptures and thousands of scriptures, but the hundreds of years it has been sealed because of its decline, making the Mogao Grottoes the "first scene" of history. In the process of historical circulation, calligraphy and painting may be copied by later generations, history books may be tampered with by later generations, and most facts are lost in the process of historical circulation. But Dunhuang is not. It's too clear
Without Dunhuang documents, we can only look at a few pages of Tubo history and the Tubo biography of the twenty-fourth history, as well as the religious history book mkas-pavi-dgav-ston written by the Lama, which is only a very small part of the ancient Tibetan materials in Dunhuang documents.
If there were no Dunhuang Grottoes, the mural calligraphy in the Tang Dynasty would be a blank forever because of the loss and damage of the Five Dynasties.
If there were no grotto murals, we would never know whether the peaceful and prosperous times, etiquette and social features recorded in the history books are true or false.