But most certainly medieval men thought of the king as ruling sub deo et lege; rightly translated, “under God and the law,” but also involving something atmospheric that might more vaguely be called, “under the morality implied in all our institutions.” Kings were excommunicated, were deposed, were assassinated, were dealt with in all sorts of defensible and indefensible ways; but nobody thought the whole commonwealth fell with the king, or that he alone had ultimate authority there. The State did not own men so entirely, even when it could send them to the stake, as it sometimes does now where it can send them to the elementary school. There was an idea of refuge, which was generally an idea of sanctuary. In short, in a hundred strange and subtle ways, as we should think them, there was a sort of escape upwards. There were limits to Caesar; and there was liberty with God.
The Well and the Shallows