Mark Gregory Pegg

​Professor of History
PhD, Princeton University
BA, University of Sydney
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    ​Professor Pegg's three books have focused on the Eurasion medieval world, the Albigensian crusade, and the Great Inquisition of 1245-1246. He teaches courses on the Middle Ages, medieval history, and Western civilization.


    Beatrice's Last Smile: A History of the Medieval World, 300-1500. (New York-Oxford: Oxford University Press, forthcoming). A comparative history of the medieval world across Eurasia.

    A Most Holy War: The Albigensian Crusade and the Battle for Christendom (New York: Oxford University Press, 2007; paperback 2009). (Polish translation from Rebis: Poznan, 2010).

    The Corruption of Angels: The Great Inquisition of 1245-1246 (Princeton: Princeton University Press, 2001; paperback, 2005).

    Selected Publications

    Peer-Reviewed Articles

    “The Paradigm of Catharism; or, the Historians’ Illusion,” in Cathars in Question, ed. Antonio Sennis (Woodbridge: Boydell and Brewer, 2016), pp. 21-52.

    “Innocent III, les Pestilentiels Provençaux et le paradigme épuisé du catharisme,” Cahiers de Fanjeaux:Innocent III et le Midi  50 (2015): 225-279.

    “A Cautionary Note,” in Center and Periphery: Studies on Power in the Medieval World Honor of William Chester Jordan, eds. Katherine Jansen, Guy Geltner, and Anne Lester (Brill: Leiden, 2013), pp. 249-262.

    “Albigenses in the Antipodes: An Australian and the Cathars,” Journal of Religious History, 35 (2011): 577-600.

    “Historians and Inquisitors: Testimonies from the Early Inquisitions into Heretical Depravity,” Primary Sources and the Study of Medieval History, ed. Joel Rosenthal (London: Routledge, 2012), pp. 98-113.

    “The Cathars and the Albigensian Crusade,” in The Byzantine and Crusader Mediterranean (6th-14th Centuries): Trade, Cultural Exchange, Warfare, and Archaeology: Festschrift for John Pryor, eds. Ruthy Gertwagen and Elizabeth Jeffreys (Aldershot: Ashgate, 2012), pp. 329-351.

    "Heresy, Good Men and Nomenclature," in Heresy and the Persecuting Society in the Middle Ages. Essays on the Work of R.I. Moore, ed. Michael Frassetto (Leiden: Brill, 2006), pp. 227-239.

    "'Catharism' and the Study of Medieval Heresy," New Medieval Literatures, 6 (2004): pp. 249-269.

    "Questions About Questions: Toulouse 609 and the Great Inquisition of 1245-1246," in Trials and Treatises: Texts on heresy and Inquisition, eds. Peter Biller and Caterina Bruschi (Woodbridge: Boydell and Brewer, 2003), pp. 111-125.

    "On the Cathars, the Albigensians and good men of Languedoc," Journal of Medieval History, 27, (2001): pp. 181-195

    "Le corps et l'autorite: la lepre de Baudouin IV," Annales ESC, 45 (1990): pp. 265-287.

    Work in Progress

    Holiness: A History: a study of holiness from the ancient to the early modern world.

    The Corruption of Angels: The Great Inquisition of 1245-1246

    The Corruption of Angels: The Great Inquisition of 1245-1246

    Mark Gregory Pegg builds a richly textured understanding of social life in southern France in the early thirteenth century. The Corruption of Angels shows how heretical and orthodox beliefs flourished side by side and, more broadly, what life was like in one particular time and place. Pegg's passionate and beautifully written evocation of a medieval world will fascinate a diverse readership within and beyond the academy.

    A Most Holy War

    A Most Holy War

    In A Most Holy War, historian Mark Pegg has produced a swift-moving, gripping narrative of this horrific crusade, drawing in part on thousands of testimonies collected by inquisitors in the years 1235 to 1245. These accounts of ordinary men and women, remembering what it was like to live through such brutal times, bring the story vividly to life. Pegg argues that generations of historians (and novelists) have misunderstood the crusade; they assumed it was a war against the Cathars, the most famous heretics of the Middle Ages. The Cathars, Pegg reveals, never existed. He further shows how a millennial fervor about "cleansing" the world of heresy, coupled with a fear that Christendom was being eaten away from within by heretics who looked no different than other Christians, made the battles, sieges, and massacres of the crusade almost apocalyptic in their cruel intensity. In responding to this fear with a holy genocidal war, Innocent III fundamentally changed how Western civilization dealt with individuals accused of corrupting society. This fundamental change, Pegg argues, led directly to the creation of the inquisition, the rise of an anti-Semitism dedicated to the violent elimination of Jews, and even the holy violence of the Reconquista in Spain and in the New World in the fifteenth century. All derive their divinely sanctioned slaughter from the Albigensian Crusade.