The divine right of kings is a (now considered archaic and defunct) justification of a king or queen's right to rule by virtue of the claim that he or she was given the right to rule by God. In some cases this line of argument was extended to assert a divine ancestry thus further ideologically legitimising the process of rule.

The notion of divine right of kings was certainly in existence anterior to the medieval period, however it was during this time that the notion became extensively used as a primarily political mechanism i.e. for increasing the power of kings within centralized monarchies relative to their subjects.

Saint Augustine in The City of God defines a Christian monarchy in his dualistic concept of Two Cities. The Two Cities are the City of God, the spiritual world, and the City of Man, the secular world. According to Augustine, the City of Man was created by God to protect the City of God and thus monarchs are enthroned by God for a particular purpose, the protection of the City of God. To question their (and by extension, God's) authority is to question God's purpose for both the City of Man and the City of God, and thus not only politically dangerous but spiritually dangerous to the point of heresy.