In the fourth year of Wude in Tang Gaozu, in order to rectify the chaotic currency system, the currency system was reformed with reference to the five baht standard in the Western Han Dynasty. The casting and circulation of Kaiyuan Bao Tong in the Tang Dynasty promoted the Tang Dynasty, whose capital was Chang 'an, to enter a prosperous period of long-term stability. Because of "baht", Zhenguan Shengshi is called "Golden baht year" because of its wealth. So, it's the Tang Dynasty.