"[A] penetrating look at the incredible power struggles of 13th-century Europe…Whalen has written a wise, in-depth, and passionate account of the struggle of the two 13th-century Popes Gregory the IX and Innocent the IV, both of whom were determined to put their political agendas ahead of the Church and their own priestly roles...This is an easy book to read, especially for anyone interested in the history, religion, and politics of the medieval world. It is well written, and the well-organized ideas help readers understand specific regions, topics, and periods. This is the resource book lecturers and students have been waiting for." (Reading Religion) "The Two Powers offers a new and convincing statement on the relations between papacy and empire in the first half of the thirteenth century and demolishes the current rather simplistic assessments of papal attitudes to Frederick II." (R. N. Swanson, University of Birmingham) "Brett Edward Whalen narrates engagingly with a wonderful eye for the telling detail or anecdote. Never the cheerleader nor the scold, he looks carefully at all sides in each major stage of the ongoing confrontation between Frederick II and the popes and makes an original contribution of paradigmatic significance." (Thomas F. X. Noble, University of Notre Dame)
