Located 45km (28 miles) southeast of Turpan, Gaochang was founded during the Han dynasty as a garrison town to supply troops engaged in the conquest of the "Western Regions." Gaochang rose to prominence, becoming the capital of the region and maintaining its influence even when it passed from Chinese hands. Xuanzang visited in A.D. 630, and the king of Gaochang was so impressed by his preaching that he took the young monk captive. Xuanzang went on a hunger strike and was released with a promise to return. He wriggled out of his pledge, returning to China by the southern Silk Route. In any event, the king was dead before he returned, as Turpan returned to Chinese control.

During the Tang dynasty, Gaochang was a thriving artistic and spiritual center for Buddhism and Manichaeism, and most relics recovered by Albert von Le Coq, Stein, and Chinese archaeologists date from this period. There is a Manichean shrine northeast of the city walls, but the contents of its library were thrown into a river 5 years before Le Coq arrived. The man feared "the unholy nature of the writings and . . . that the Chinese might use the discovery as a pretext for fresh extortions."

Gaochang is a significant site, but aside from the city walls and the restored Buddhist temple, the weathered mud-brick buildings are hard to discern.