Ozment, Steven E. The Age of Reform: 1250-1550 : An Intellectual and Religious History of Late Medieval and Reformation Europe. New Haven, Conn. ; London: Yale University Press, 1980. Kindle Electronic Edition.
Chapter 5, “On the Eve of the Reformation” pp. 182-222. Part 1, “The Growth of Monarchy” pp. 182-189.
Ozment cites the political expansion to “national” size rather than the city-state model, as well as security from foreign aggression as developments important to the Reformation. The rise of the powerful monarch tended to replace the powerful churchmen. Ozment gives examples of this process especially in France, England, and Spain. Germany and Italy did not develop as strong and centralized governments but still consolidated power in different regions. Ozment observes on p. 187 that legislative affirmations of the superiority of kings over papal authority followed the strengthening of political realms. Following this legislation it became more common for governments to regulate churches and religious appointments.