Pei County
The raging wars inflicted upon Xuzhou until the Emperor Taizong of Tang's enthronement in 626. Keeping the northern rebellions and warfare a distance gave Xuzhou scope for developing during the most period of the Tang dynasty. According to the "Old Book of Tang" and the "New book of Tang", in 639, the total population of Pengcheng County, Fei County and Pei County was only 21,768, versus 205,286 in 742.