Eight years after the publication of his edited volume L'espace du diocèse: Genèse d'un territoire dans l'Occident médiéval, Ve-XIIIe siècle (Presses Universitaires de Rennes, 2008), Florian Mazel has synthesized his own thinking on the origins of the medieval diocese in the form of an extended essay of nearly four-hundred pages, excluding endnotes. Mazel's thesis is a rejection of the longstanding view of these dioceses as simply co-opted and repurposed Roman civitates, with bishops taking the place of urban magistrates. Instead, he proposes a discontinuous development, which he affixes to a periodization schema that divides the European Middle Ages into two major epochs, in which the Carolingian era was merely a “false start,” and the eleventh and twelfth centuries marked the true turning point (374). In its treatment of the centuries that immediately followed the dissolution of Roman imperial rule in western Europe, Mazel's schema echoes the work of other historians of early medieval social and urban history, including Simon Loseby (whose many publications surprisingly are absent from Mazel's bibliography), who date the decline of ancient cities' administrative significance to the early seventh century. While the association between episcopal sees and urban centers continued, Mazel argues that episcopal jurisdiction in the early Middle Ages was defined and circumscribed not by fixed territorial borders but rather by heterogeneous amalgamations of institutions and places controlled by individual bishops at particular moments in time. The diocese, as a territorial construct, largely was a post–Gregorian Reform “medieval” innovation, the product of an expansion of episcopal jurisdictional and fiscal authority, the definition and sub-division of diocesan space, the regularization of administrative instruments such as the episcopal visit and diocesan synod, and the invention by individual sees of sometimes dubious “memories” of their origins and history that could be used to justify contemporary claims to space. While comparisons can be drawn, therefore, between the ancient civitates that had functioned as administrative satellites of imperial Rome with the thirteenth-century episcopal dioceses that enjoyed a similar relationship with papal Rome, Mazel sees no unbroken continuity from one to the other.

Despite its chronological breadth, Mazel's study concentrates geographically primarily on Gallic dioceses, with particular attention paid to those located in Provence and in the former Roman province of Lugdunensis Tertia. While thus grounding his proposed historical models in a combination of detailed case-studies and comparative examples, his argument for discontinuity consciously breaks with a longstanding trend in scholarship to identify the Gallic Church as the preserver of romanitas. Mazel certainly is correct in his assertion that the latter view all too often assumes unbroken continuity, with insufficient attention paid to the nuances of incremental change. In the Merovingian period, as Mazel shows, it is demonstrable that new episcopal sees did appear (in some cases ephemerally) while others went vacant or merged (35–36). Additionally, bishops certainly did not consistently enjoy uniform control over the institutions and personnel within the space over which they claimed authority and likewise had to defend, on occasion, their jurisdictional claims against encroachments by rival parties, including fellow prelates.

At the same time, while the spatial dimensions of individual dioceses might be characterized more by plasticity than consistency, as suggested by Mazel, the provincial organization of the Gallo-Frankish Church nevertheless enjoyed a surprising durability, if by no means rigidity, between the sixth and eighth centuries. Furthermore, there are several reasons to doubt whether the political events of the first half of the eighth century necessarily marked a significant crossroads in ecclesiastical matters. Paul Fouracre (whose publications, save one, also are absent from Mazel's bibliography) and others have questioned, for example, Charles Martel's reputation as an unprecedented purloiner of ecclesiastical policy, as well as the extent to which lacunae in diocesan episcopal lists are compelling evidence for an increase in vacant seats during this period. In general, it is not obvious to what extent the handful of discernible cases of disruption of episcopal governance are representative of larger trends. The so-called “episcopal republics” of the late seventh and early eighth centuries, for example, whose dismantling Mazel credits to Charles Martel and his successors, may well have been few in number and lacking in longevity.

Moreover, as Fouracre and others have suggested, the assumption of ecclesiastical decadence in this era may be too reliant on the problematic testimony of Saint Boniface. Mazel's periodization, in contrast, assumes that the Carolingian integration of bishops into the administrative apparatus of the realm was partly a restorative effort following decades of struggle with local aristocrats and property confiscations (73–77). However, while the Carolingians demonstrably attempted, with mixed success, to regularize ecclesiastical governance in the Frankish realm, it does not necessarily follow that the provincial administration of the Gallo-Frankish Church had required extensive repair.

Nevertheless, in questioning fundamental assumptions about ecclesiastical space, Mazel has performed an important service. While his essay might have benefited from additional engagement with English language scholarship (along with Loseby and Fouracre, notable bibliographical omissions include Susan Wood on proprietary churches, William Klingshirn on Caesarius of Arles's efforts to build Christian community, and A. C. Murray on immunities), its breadth remains impressive. Those scholars who emphasize continuity, in particular, now must take into account Mazel's insights into the ways in which bishops defined and attempted to control space over time, even if they do not accept in full his periodization schema. This is a stimulating book that ought to prompt both discussion and debate.