21 But afterward, when Christian rulers were at the head of States, the Church insisted much more on testifying and preaching how much sanctity was inherent in the authority of rulers. Hence, when people thought of princedom, the image of a certain sacred majesty would present itself to their minds, by which they would be impelled to greater reverence and love of rulers. And on this account she wisely provides that kings should commence their reign with the celebration of solemn rites; which, in the Old Testament, was appointed by divine authority.(28)
Source: Diuturnum (Vatican.va)