Datong 's position to the north and west of the mountains that separate the North China Plain  from the nomadic steppes made it for centuries an important center of interaction between Chinese and outside cultures of religious and artistic synthesis , of intermarriage and trade . But so too was it the site of heavily militarised fortifications that both physically and visually enforced that separation between the Chinese and Tatar realms. The city was an important power base in the Han the capital of Northern Wei dynasty , a secondary capital during the Liao and Jin dynasties and strategic fortification during the Ming and Qing. The extensive rebuilding projects of recent times might be seen as the continuation of the city's prominent political culture.