“Even in remote antiquity the sand-swept height overlooking the desert river valley was known as the Wonderful Cliff or the Precipice of the Immortals. It had probably been considered a locus of spiritual power for centuries when in 366 a wandering monk named Yuezun, “resolute, calm, and of pure conduct...traveling the wilds with his pilgrim’s staff, arrived at this mountain and had a vision of a golden radiance in the form of a thousand Buddhas. Thereupon he erected scaffolding and chiseled out the cliff to make a cave.””