In modern times just as in medieval times, religion and politics are inseparable because leaders feel a need justify their actions to themselves and to their people. An obvious means of doing this is to claim divine support; and the more pious the leader the more likely s/he is to claim this support. Yet these claims are not necessarily hypocritical; the leader honestly believes that they have divine support, that they are waging war on behalf of their god. The fact that they honestly believe this, however, doesn’t mean that they are correct; it is possible to be honestly mistaken.

Medieval monarchy had an additional religious dimension because, whereas modern western governments derive their right to rule from the democratic will of the people, medieval monarchies derived their right to rule from God. When a monarch assumed office, s/he took an oath to God that bound the monarch to do God’s will. Hence, in theory a monarch was acting on God’s behalf. In actual practice, the monarch’s subjects would often say that the monarch was acting against their oath. But this was a two-way agreement; God also had to protect the monarch.

That said, the evidence that survives about medieval monarchs indicates that they did believe in God and considered themselves answerable to God, although they also expected God to look after them. They also did not always pay much attention to the religious regulations of the Church: so King John of England (1199-1216) would go hunting during Lent, when the Church forbade hunting, and then give generously to the poor to make up for breaking the Church’s rules.