Medieval Political Theology, by contrast, was based upon the concept of original sin, ie the flawed nature of man. Thus it's a bad idea to give too much power to any one person or institution.
That's why the power of Medieval monarchs were always constrained by the rival powerblocks of the aristocracy, the Church, communes, etc. As far military matters goes, this meant Medieval armies were largely ad-hoc formations and participated in relatively small-scale wars. There was brutality at times, especially with Mongol looting, but again it always a more haphazard affair than say Sherman's march to the sea.