The Zhou rulers claimed to have won the Mandate of Heaven because it provided them with the legitimacy to rule over China. According to the concept of the Mandate of Heaven, which originated during the Zhou dynasty, the ruler was believed to be chosen by the gods and had their divine approval to rule. The Mandate of Heaven was based on the belief that the gods bestowed the ruling dynasty with their blessings and support as long as the ruler governed with virtue and righteousness. If a ruler failed to uphold these qualities, it was believed that they would lose the Mandate of Heaven, leading to their overthrow by a new dynasty. Therefore, claiming to have won the Mandate of Heaven was essential for the Zhou rulers to legitimize their rule and gain the support of the people. It provided them with a justification for their authority and secured their position as the rightful rulers of China.
