Wulan County, which was located on the middle section of the northern route of the Silk Road within today’s Baiyin City in Gansu Province, and which was established and abolished several times, can be associated with the historical changes at that time to the benefit of academic research. It was first established in the third year of the Baoding er(562) during the Northern Zhou and may have been abolished in the sixth year of the Jiande era(572). It was reestablished in the ninth year of the Wude era during the Tang dynasty and later came under Tibetan control in the fourth year of the Jianzhong era(783). In the Tang dynasty, Wulan County bounded the "Bailu Beacon" on the west and had three seats of jurisdiction spread over three townships: one in charge of the city seat and the nearby area, mainly including the riverside area in today’s Jingtai and Jingyuan;one in charge of the New Spring Oasis area irrigated by the New Spring in the Tang dynasty(today’s Yunwei River oasis), located in the modern town of Luyang in Jingtai; the third covered the salt marsh area to the east of Shawo town in today’s Jingtai.
