[2] During the Early Han, "a defensive line was established from Jiuquan ('Wine Springs') in the Gansu Corridor west to the Jade Gate Pass at its end.

"[3] Travellers to 'The Western Regions' (西域, Xiyu) left China through the famous Yumenguan 玉門關, or 'Jade Gate Frontier-post,' named for the many jade caravans that passed through it.

The original Jade Gate was erected by Emperor Wudi (Emperor Wu of Han) soon after 121 BCE and its ruins may still be seen about 80 kilometres (50 mi) to the northwest of Dunhuang which was, until the 6th century, the final outpost of Chinese territory for caravans on their long caravan journeys to India, Parthia, and the Roman Empire.

In the third and fourth centuries turmoil swept through Central Asia, disrupting overland trade, and the sea route via India began to supplant it.

In 1907, Sir Aurel Stein found bamboo slips naming the site as Yumenguan, and in 1944 Chinese archaeologists discovered relics that confirmed this.