Vermigli's biblical writings frequently address political matters. He followed the Aristotelian view that political authority is instituted to promote virtue, and that this includes religion as the chief virtue. Vermigli defended the standard English Protestant doctrine of Royal Supremacy, that kings, so long as they obey God, have the right to rule the church in their land, while Christ is the only head of the universal church. He denied the idea that the pope or any other ecclesiastical authority could exercise authority over a civil ruler such as the king, an important issue at the time given the conflicts between Pope Clement VII and Henry VIII at the beginning of the English Reformation. While Vermigli charged the civil magistrate with enforcing religious duties, he followed Augustine's distinction in the "City of God" between the spiritual sphere (in Vermigli's words the "inward motions of the mind") and the "outward discipline" of society. The civil magistrate's authority is only on external matters rather than inward and spiritual religious devotion. Vermigli's theological justification for Royal Supremacy was used by the framers of the 1559 Elizabethan Settlement, the imposition of Protestant worship based on the "Book of Common Prayer" as the state religion.