The Mandate of Heaven was a concept established long before the unification of China, it believes Heaven will provide the chinese people with just rulers, it was applicable to both emperors and kings and could be inherited by their heirs but it didn't require the ruler to be of noble birth, only that he be recognized as a good and powerful leader (imperial dinasties such as the Ming and Han were founded by lowborns), poverty and natural disasters could be evidence that the Mandate of Heaven was lost, weakening the ruler's authority.