"Christianization without religion": this is how Ristuccia asks us to revise traditional paradigms of Christianization. Ristuccia's careful and well-written study of a Christian feast, Rogationtide, in early medieval Europe joins recent (and older) scholarship that exhorts scholars to dispense with religion as an anachronistic and unhelpful concept for making sense of the pre-modern world.  Instead, Ristuccia urges us to understand Christianization as "primarily a ritual performance" through which Christian identity, and thereby Christians, were made and re-made (210). 
Ristuccia begins with the earliest literary evidence for Rogationtide, situating the feast's roots, and its subsequent dissemination, in the context of the waning urbanism of late antique Gaul. He argues that this feast provided a way of shoring up communal solidarity, of preserving Romanness, in the face of external and internal threats to communities' identities. In keeping with the considerable variation found in its celebration, Ristuccia proposes a fairly flexible definition of Rogationtide: "More specifically the Rogation Days entailed four structural elements: (1) a three-day duration, (2) annual celebration at a fixed time, usually in the weeks around Ascension and Pentecost, (3) a procession of laity and clergy together, and (4) accompanying penitential practices such as fasting and prayer" (28).  (In chapter 4, however, the last of these elements appears less certain, as Ristuccia raises the possibility that feasting, so often condemned by clergy, might be seen as an alternative way of marking the feast.)
At the heart of a book (chapter 3, "Beating the Bounds of the Christian") is Ristuccia's demonstration of how the feast, and in particular its procession, symbolically constituted and embodied the community's "Christian unity and solidarity" (97). Despite the emphasis on ascetic dress and fasting, this was by no means a levelling of society; to the contrary, Ristuccia stresses that social positions were played out and affirmed in the ordering of participants in the procession. Analogously, Ristuccia suggests that the route of these processions mirrored and affirmed a community's preexisting topography of Christianity. In this chapter Ristuccia also addresses how Rogation homilies reinforced the "theme of Christian solidarity," especially by means of foundation legends for the feast--whether this involved drawing on the repentance of the city of Nineveh as a biblical precedent for Rogationtide, by relating the story of Mamertus and the Rogationtide of Vienne, or more popularly, repositioning Gregory the Great and the "Greater Litany" at the origins of the feast. Chapter 5 returns to homilies preached at Rogationtide to trace how, beginning in the eighth century, preachers used the occasion to provide Christian instruction, especially on the Lord's prayer.
Throughout, Ristuccia is eager to correct what he argues, convincingly, are two long-standing scholarly misconceptions about Rogationtide: firstly, that Rogationtide was in its origins and concerns primarily an agrarian feast (given this, the image on the dust jacket, with its procession against the backdrop of agricultural fields, is an odd choice), and, secondly, that Rogationtide was a pagan survival or Christian replacement for the ancient Roman feast of the Ambarvalia. Chapter 2 traces how this latter misconception arose; this is a fascinating story of how the idea of "ritual substitution" as a "standard policy of the church" (95), combined with Carolingian interpretations of Roman feasts, gave fuel to later medieval and early modern re-interpretations of the feast. Above all, this chapter provides a salutary reminder of the degree to which early modern scholarship (and polemic) continues to cast a long shadow over our understanding of the early medieval past.
A great strength of Ristuccia's analysis is his attentiveness to change and local diversity in celebrations of Rogationtide, an approach that fruitfully parallels recent work in ancient religion.  Ristuccia attributes Rogationtide's distinctiveness from other feasts and "its long-lasting preeminence" (26) to the fact that initially "it was vague, flexible and evolving" (39) and thus was eminently suitable to the "instability and localism of the post-Roman world" (31). In turn, however, it was the efforts of Carolingian rulers and their advisors that established the feast as a more uniform observance. In chapter 4 Ristuccia addresses three specific moments when Rogationtide became the flashpoint for dissent; this, he argues, shows how "different performances of the feast embodied different visions of the community" (175).  Here Rogationtide emerges most clearly as an occasion for defining, and attempting to negotiate the definition of, what it meant to be Christian.
In his conclusion Ristuccia provocatively claims that "[a] Latin West between the polis and the parish had its own institution--the Rogation procession--for organizing local communities" (210). Readers may not all be persuaded by the notion of "Rogationtide" as an institution of comparable social significance to the polis or the parish. But persuasive and well-argued is Ristuccia's thesis that it was festivals like Rogationtide that, together with other rituals, forged new Christian communities--bridging the transition from polis to parish, and that "it is in the particulars, the pragmatics, the often obsessive details of specific rituals [...] that the task of Christianizing" was carried out (210).
1. For example, Carlin A. Barton and Daniel Boyarin, Imagine No Religion: How Modern Abstractions Hide Ancient Realities (New York: Fordham University Press, 2016).
2. In his introduction Ristuccia introduces the concept of a "Christian commonwealth" (res publica christiana) as appropriate for understanding the ensuing "network of Christian polities joined together through common faith, institutions, and rites," but in subsequent pages the implications of this remain a relatively unexplored thrust of his argument.
3. Nevertheless, Ristuccia insists on a firm differentiation between Rogationtide and the Roman Greater Litany even though, as he discusses, the two exerted an influence on each other and indeed were often confused.
4. For example, Harriet I. Flower, The Dancing Lares and the Serpent in the Garden: Religion at the Roman Street Corner (Princeton: Princeton University Press, 2017).
5. For recent similar avenues of research, see Shane Bobrycki, "The Flailing Women of Dijon: Crowds in Ninth-Century Europe," Past & Present: A Journal of Historical Studies (2018), which demonstrates how collective behavior in the early medieval Europe could threaten (or be seen as threatening to) the power of established elites; and Kate M. Craig, "Fighting for Sacred Space: Relic Mobility and Conflict in Tenth-Eleventh-Century France," Viator 48.1 (2017): 17-37, which addresses processions as occasions ripe for expressions of competition and dissent.