Papacy and Law in the Gregorian Revolution: The Canonistic Work of Anselm of Lucca

The Italian Crusades: The Papal-Angevin Alliance and the Crusades Against Christian Lay Powers, 1254-1343

The Pope Who Quit: A True Medieval Tale of Mystery, Death, and Salvation

Innocent III: Vicar of Christ or Lord of the World?

The Abacus and the Cross: The Story of the Pope Who Brought the Light of Science to the Dark Ages

The Historia Pontificalis of John of Salisbury (Oxford Medieval Texts)

The Early Papacy: To the Synod of Chalcedon in 451

The 1007 Anonymous and Papal Sovereignty: Jewish Perceptions of the Papacy and Papal Policy in the High Middle Ages / Hebrew Union College Annual Supplements 4

Byzantine Rome and the Greek Popes: Eastern Influences on Rome and the Papacy from Gregory the Great to Zacharias, A.D. 590-752

The Papacy and Crusading in Europe, 1198-1245

Innocent III: Vicar of Christ or Lord of the World?

Kardinale Im Konklave: Die Lange Sedisvakanz Der Jahre 1268 Bis 1271