 Under the Sui dynasty, the capital of Chang'an was renamed Da Xingcheng and its outer wall was expanded to cover a perimeter of 35 km.Under the Tang dynasty, the capital of Chang'an's outer walls measured 9.72 km east to west by 8.65 km north to south.Under the Jin dynasty the capital of Zhongdu had walls covering a perimeter of 24 km and reached a height of 12m.