The reason why the Han Dynasty was divided into the Eastern Han Dynasty and the Western Han Dynasty was that it was in a state of extinction in the middle of the Han Dynasty and was interrupted and usurped by Wang Mang. The capitals were different, with Chang 'an as its capital and the Eastern Han as its capital. In order to distinguish the Han Dynasty before the New Dynasty from the Han Dynasty established by Liu Xiu, later historians named it the Western Han Dynasty and the Eastern Han Dynasty respectively.