The Daoist caretaker
王圆箓 found it in 1900 behind a painted wall. It held sutras, contracts, letters and paintings in Chinese, Tibetan, Sanskrit and other languages, sealed around the year 1000, among them a Diamond Sutra printed in 868, the oldest dated printed book known. Many were later taken to London, Paris and other cities by foreign explorers, and their study became
敦煌学.