This episode explores the connection between the martial arts of the great Song generals’ tradition and Chinese theatre, which emerged during the height of the Yuan Dynasty.
I would also recommend this short, funny and smart crash course on Chinese Theatre as background ‘reading’:
A lot of the “x number of shoes, y number of hairdos” regulatory stuff was added later by the Confucians from the Ming onwards. In the Yuan it was much more Vale Tudo in spirit ?
To see some Yuan Dynasty plays we talk about in action I’d recommend this page, which also gives some more background on Yuan Zaju plays.