What are the theories about the art of opera in ancient China?

Ancient Chinese theories on opera art are very rich in content, mainly including the principles of opera art, the theory of opera literary creation, the theory of opera stage art, the theory of opera rhythm, the theory of opera history, etc.; they cover a wide range of fields, including the sociology of opera and the psychology of opera

Studies, opera aesthetics, opera morphology, opera philology, opera pedagogy, etc.

From the perspective of its development process, opera theory can be roughly divided into five periods: the first period from pre-Qin to Song Dynasty is the beginning period of opera theory; the second period is the Yuan Dynasty, which is the development period of opera theory; the third period is the Ming Dynasty.

The period of prosperity and development of opera theory; the fourth period from the early and mid-Qing Dynasty was the climax period of opera theory; the fifth period from the late Qing Dynasty to the early Republic of China was the period of modern opera theory.