Meng Tian
The northward bend of the Yellow River is an area of considerable strategic importance that had been part of the State of Zhao during the early Warring States period. During this period it was called Jiuyuan, and was a commandery. As Zhao gradually weakened, the area fell under Xiongnu control, only to be reconquered during the Qin Dynasty by a large expedition led by the general Meng Tian.