The Mandate of Heaven is a Chinese political doctrine that justifies imperial rule in terms of approval by the gods. The emperor was referred to as "Son of Heaven" to reflect such approval. The doctrine first appears in a speech given by the Duke of Zhou after his victory over the Shang in 1027 BC. Traditional historians agreed that the Shang lost its mandate due to the immoral behavior of its last ruler.
[source: Conservapedia (DNS seems sabatoged as direct links don't load reliably)