[Perun]

Actually the Church held the corruption of monarchs in check. Yet there was the Holy Roman Emperor who could hold the corruption of the Papacy in check, as he did during the early Medieval period. Plus monarchs had checks on their power by the aristocracy. The notion of an all-powerful ruler is completely alien to Catholic social doctrine. That notion only began to arrive with the secularism of the Renaisance and the influence of men like Machiavelli.