(2) Ou Yangxun, Yan Zhenqing and Liu Gongquan. Famous calligraphers in the Tang Dynasty came forth in large numbers; Regular script entered a prosperous period in the Tang Dynasty; It promoted the development and prosperity of calligraphy art.
(3) Popularization and popularization. The development of commodity economy, the prosperity of urban economy and the expansion of citizen class.
(4) Politics and economy are the basis of culture, which determine the nature and development direction of culture; Culture provides impetus for political and economic development.