i mean why not the Song dynasty? first of all, its timeline lies in the 13th century, doesn't it fit more the circumstances of Mount&Blade original spirit than the Ming dynasty? secondly, during Song, China is devided into 2 parts, the Southern Song in the south and the Jin dynasty in the north, along with the mongols in the back, while Ming dynasty united China, so what's in fun in that?
here's two maps of the Song Dynasty, one in western perspective, one in Chinese perspective.
in the Chinese version:
Southern Song in
grey
Jin in
purple
Dali in
yellow
Tibet in
green
Western Xia in
pink
Mongol in
orange
Goryeo in
cyan