Surveys of the expansion of papal authority in the Middle Ages tend to highlight the Gregorian reform or the bull Unam Sanctam of 1302. Few consider a slower revolution, but one that has left a more lasting impression: the dogma of papal infallibility. This may be because a definitively articulated infallibility is the product of Catholicism's institutionalized modernity. The First Vatican Council of 1870 stated that in pronouncements ex-cathedra, the pope is infallible, and his words stand permanently on their own, without requiring support from the church. Nonetheless, as Donald Prudlo shows in his erudite and persuasive monograph, papal infallibility was every bit a product of the Middle Ages, rooted not only in the intellectual life of the medieval church, but also in everyday belief and practice.
In Certain Sainthood, Prudlo links infallibility to the centralization of sainthood in the medieval western church. Between 1200 and 1350, the papacy's efforts to monopolize the recognition of saints met both with resistance and enthusiasm. Mendicants dominated the roster of new saints, thus obliging the curia and (Franciscan and Dominican scholars) to defend specific canonizations, and the authority of the pope to grant them. In the process, these men honed a general argument that became “theological consensus” by the end of the high Middle Ages (9).
Prudlo argues that canonization was a claimed papal prerogative by the mid-thirteenth century, at which point popes began to initiate inquests into sanctity rather than simply approve petitions. Sparingly used in the eleventh and twelfth centuries, papal authorization became part of canon law in 1234 when Raymond de Peñafort inserted into the Liber Extra of then-Pope Gregory IX a letter from Pope Alexander III forbidding ad hoc sanctification. Prudlo follows historians of canon law up to this point, but then departs from them to argue that local communities continued to elevate their own saints. Like Andre Vauchez and Michael Goodich before him, Prudlo treats sanctity essentially as a product of popular veneration. The gulf between the pronouncements and the practice of sanctification required decretalists to keep honing a defense of papal prerogatives.
Challenges to papal prerogative coalesced around anti-materialist heresies: Cathars and Waldensians who opposed the cult of saints in general. In turn, heresy prompted the popes to advance mendicant inquisitors to sainthood, which then led to further challenges. Thanks to the inextricability of papal authority and canonization, by 1300 it had become heretical to oppose a pope's decisions on sanctity.
After establishing heretical opposition as a driver in these debates, Prudlo turns to territory already associated with papal infallibility: canon law, theology, and controversies over mendicant poverty. However, he disagrees vehemently with Brian Tierney, who gave primacy to Peter John Olivi's writings from circa 1270, and focuses instead on earlier work by Bonaventure and Aquinas. The final chapters deal with the emergence of heterodox sanctity, especially among the beguines, a development that generated further imperatives for the defense of papally sanctioned saints.
Here, then, is an intersection of intellectual history and lived religion—not easy to come by or achieve in studies of the medieval church. Philosophically speaking, Prudlo owes much to Herbert Grundmann's argument that evolution in Christian thought occurred as waves of popular engagement, orthodox or otherwise. For Prudlo, the canon lawyers who implied or partially asserted infallibility were responding less to each other than to the “trickle up” imperatives of ordinary Christians, including those deemed heretics. The story of papal infallibility therefore requires that we understand medieval heresy as a set of cogent arguments, beliefs, and criticisms rather than as the social construction of an “other.” It validates David Nirenberg's remark that we cannot give due regard to what these men and women were willing to die for if we treat their beliefs as somebody else's invention (review of The War on Heresy, by R. I. Moore, Speculum 88, no. 4 [October, 2013]: 1132–1133).
While there is much to admire in his argument and approach, Prudlo sometimes struggles with presentation. The book oscillates between chronological and thematic organization. The effort to interweave theology and lived religion also means that a chapter on mendicant scholars suddenly shifts to a discussion of heretical opposition to mendicant saints. The discussion of decretalists drifts too far from the central argument, and, while deeply satisfying in their own right, the sections on heresy do the same. These are mere quibbles, but another kind of oscillation is worth questioning: Is this a book about the articulation of infallibility or about the evolution of “implied infallibility”? It is not always easy to distinguish between the two, yet I would argue that such a distinction is imperative.
Among this book's many contributions, the most valuable may be its description of the impact of fringe groups on a center. Heterodoxy brought to the fore mendicant preachers and inquisitors who then became saints, the same saints whose defense forced an articulation of papal infallibility. Prudlo thus shows that papal hierocratic claims were made not in conformance to any long-term political project, but reactively, responsively.
Fittingly, these claims come to life on communitarian occasions, and canonizations number among the most solemn and historically freighted. Cognizant of a dialogue with the church's modernity, Prudlo begins with John Paul II's canonization of the seer of Guadalupe, a figure who may not even have existed. The choice is prescient, given even more recent controversies, such as Pope Francis's canonization of the missionary Junipero Serra. In recognizing the contestations that produced the language of infallibility, the historian takes religion seriously, as living community that grows in multiple and often adversarial directions. Papal infallibility serves as a guardrail for debate and criticism, and not as a mechanism of silencing.
