Around the year 1000 a side chamber off Mogao Cave 16, near Dunhuang on the edge of the Taklamakan desert, was filled with tens of thousands of manuscripts and printed items, walled up and painted over. Why is still argued. One reading is emergency storage against an approaching threat. Another is that this was a repository for worn, superseded and damaged texts that could not simply be destroyed because of what was written on them. The contents fit the second reading better than the first, being mixed, incomplete and heavily used.
The chamber stayed sealed for nine hundred years. Wang Yuanlu, a Daoist who had taken on the care of the caves, found the door during restoration in 1900. Word spread slowly, and then not slowly at all. In 1907 Aurel Stein, on a British expedition, negotiated with Wang and left with thousands of items including this scroll. Paul Pelliot came for France in 1908, and Russian and Japanese expeditions followed. Within a decade the library was scattered across a dozen institutions on three continents.
That dispersal is not settled history. China regards the removals as looting and has sought the material's return. The International Dunhuang Programme, which digitised the collections and reunited them online, is a partial answer to a question that remains open in every other respect.