As a place name of the frontier, Hanhai had been referred to the Lake Baikal. Till the prosperous period of Tang Dynasty, it added to other two meanings, namely, "vast desert" and "pool on the top of the Tianshan Mountain" (Heavenly Lake). During the period ruled by Empress Wu Zetian of the Tang Dynasty, the Huihe (an ancient Chinese tribe), whose headman held the post of military govemor of Hanhai, migrated westwards so that Hanhai gradually became a substitute name for the westem desert. Subsequently, the Hanhai army stationed at Tingzhou, which related Hanhai to the western region. Under the Yuan Dynasty the Hang' aishan Mountain was named as Hanhai by local Huihe residents, because the Hanhai military prefecture of Tang Dynasty had ever been established there. And during the period of Ming- Qing dynasties, Hanhai became a special name of desert.