Dynastic cycle

According to Chinese political theory, every dynasty goes through the so-called dynastic cycle:

A new ruler united China and founded a new dynasty.

China under the new dynasty achieved prosperity and a new golden age.

The royal family of the dynasty began to decay and China was on the way to decline and instability.

The dynasty finally lost the Mandate of Heaven, i.e. their legitimacy to rule. The Mandate of Heaven would then be passed to the next dynasty.