Definition for Mandate of heaven
From Biology Forums Dictionary
The Mandate of Heaven is a Chinese political and religious doctrine used to justify the rule of the Emperor of China. According to this belief, heaven — which embodies the natural order and will of the universe — bestows the mandate on a just ruler, the Son of Heaven. If a ruler was overthrown, this was interpreted as an indication that the ruler was unworthy, and had lost the mandate. It was also a common belief that natural disasters such as famine and flood were signs of heaven's displeasure with the ruler, so there would often be revolts following major disasters as citizens saw these as signs that the Mandate of Heaven had been withdrawn.