Title: Byzantine Rome and the Greek Popes: Eastern Influences on Rome and the Papacy from Gregory the Great to Zacharias, A.D. 590-752, Author: Andrew J. Ekonomou
Title: Papal Ceremonial at Rome in the Twelfth Century, Author: Susan Twyman
Title: The English Church and the Papacy: From the Conquest to the Reign of John, Author: Zachary Nugent Brooke
Title: The Papacy, 1073-1198: Continuity and Innovation, Author: I. S. Robinson
Title: The Popes and the Papacy in the Early Middle Ages (Routledge Revivals): 476-752, Author: Jeffrey Richards
Title: The Spanish Church and the Papacy in the Thirteenth Century, Author: Peter Linehan