500
This is the Dynastic Cycle.
What is the cycle wherein:
1) New Dynasty gains power /claims mandate of heaven 2) establishes peace and prosperity/has mandate of heaven 3) Dynasty declines/corruption, higher taxes
4) Disasters such as floods, famine, peasant revolts, invasions
5) Dynasty seen as having lost mandate of heaven/rebellion justified
6) Dynasty overthrown through rebellion/new dynasty emerges
[THEN, RETURN TO STEP 1]