Question

Witch dynasty used the Mandate of Heaven to justify its replacement of the previous dynasty

Answer 1

the Zhou dynasty

The concept of the Mandate of Heaven was first used to support the rule of the kings of the Zhou dynasty (1046–256 BCE), and legitimize their overthrow of the earlier Shang dynasty (1600–1046 BCE).

Answer 2

The Zhou created the Mandate of Heaven. The idea that there could be only one ruler of China. :)