Mandate of Heaven
The emperor—embodying a heavenly mandate to judicial and executive authority—was on a social and legal tier above the gentry and the exam-drafted scholar-officials. Under the principle of the Mandate of Heaven, the right to rule was based on "virtue"; if a ruler was overthrown, this was interpreted as an indication that the ruler was unworthy, and had lost the mandate, and there would often be revolts following major disasters as citizens saw these as signs that the Mandate of Heaven had been withdrawn.