In this exceptionally learned, well-written, and important monograph, Gaposchkin makes a singular contribution to not one but two fields: liturgical studies and crusades history. For specialists of the liturgy, Gaposchkin demonstrates how the evolution of liturgical ideas and practices between the late eleventh and fifteenth centuries must be understood as a contingent process that was essentially inflected by the changing contexts of crusading in the Levant. In this effort, she builds skillfully upon the work of Amnon Linder, among others. For crusades scholars, Gaposchkin illustrates how liturgical expression was a key medium through which Latin Christendom constructed, refined, and, when necessary, reworked the devotional ideology of the crusading project. Prayers, masses, hymns, supplicatory processions, alms, fasting—these were the “invisible weapons” that necessarily complemented the corporeal arms of crusaders in the prosecution of holy war. Through the adaptation and communal performance of such liturgical forms, Latin Christians sought to articulate before God their evolving ideas about confessional identity, spiritual ideals, and the arc of providential history. In this respect, Gaposchkin's monograph positions itself at the leading edge of a growing body of recent scholarship investigating the cultural impact of the crusading phenomenon.

The book's seven chapters are preceded by a preliminary section in which Gaposchkin orients the reader by surveying both the chronology of pre-modern crusading to the Levant and various technical concepts necessary for apprehending the medieval liturgy. The book's chapters are followed by three appendices which collate some of the key information contained in Gaposchkin's geographically diverse source base of liturgical manuscripts; as many of these materials yet remain unpublished or are otherwise difficult to access, such appendices are a welcome supplement. In chapter 1, Gaposchkin illuminates how the language and ideology of early crusading took shape within the vibrant devotional contexts of pre–1095 liturgical traditions. Rites of penance, militant rhetorical frameworks of spiritual warfare, and the dual penitent-militant theology of the cross interwove to yield a complex ideological core for the nascent crusading project. As a central part of this process, the temporal conflict between Latin Christians and “Saracens” was enduringly signified as both parallel to and proxy for the eschatological conflict between God and Satan.

Chapter 2 focuses on the development of the rite of departure for crusade. Building upon the work of Giles Constable, among others, Gaposchkin argues that it was through the synthesis of various traditional blessings for swords, standards, crosses, scrips, and staves that the crusade departure rite became the mechanism by which a crusader was temporarily reconstituted as a liminal actor—namely, an armed pilgrim in a quasi-monastic penitential quest of sacred violence that mirrored the cosmological battle between good and evil. In chapter 3, which is based on a close reading of the narrative sources for the First Crusade, Gaposchkin contends that the extensive performance of the liturgy on crusade anchored its lay and clerical participants, as well as the enterprise itself, in inescapably religious terms. In the devotional imagination, the first crusaders were retrospectively understood to have been a cohesive spiritual community that had undertaken a sacramental act in loyalty and defense of God, and in so doing had brought about an epochal event in salvation history.

Chapters 4 and 5 examine twelfth-century liturgical commemorations of the July 15, 1099 conquest of Jerusalem within the Latin East and the Latin West, respectively. Exemplifying an overtly apocalyptic bent, the eastern liturgy drew upon existing constructs for Advent and Epiphany, as well as biblical prophecies such as Isaiah, in order to memorialize the liberation of Jerusalem from Muslim occupation as the end of a new Babylonian captivity: through crusading, Latin Christendom had advanced providential history and primed the Second Coming. Western commemorations, in any case uncommon, tended to be diverse, idiosyncratic reflections of local liturgical traditions rather than coherent vessels for apocalyptic acclamation, though such commemorations did share a bellicose and triumphant tone with their eastern counterparts.

In chapter 6, Gaposchkin illuminates how the liturgical response to the 1187 fall of Latin Jerusalem further embedded crusade within the heart of Latin Christian identity. Through the initiative of Pope Innocent III in particular, prayers, clamors, and public processions became institutionalized means by which Latin Christians sought to expiate their sins, which had enabled the loss of Jerusalem, while also beseeching God's aid in reclaiming the Holy Land. After the 1291 fall of Acre, Pope Clement V even promulgated an encyclical that revised the Mass rite itself, whose “essential function . . . was now [to advocate] to God for help in fighting the crusades” (225). Shifting to the later fifteenth century, chapter 7 explores how the emergent genre of the “Dedicated War Mass,” as well as other ritual texts, repurposed earlier liturgical forms which had been devised for crusading in the Holy Land in order to confront the Ottoman threat in eastern Europe. According to Gaposchkin, these early modern adaptations of medieval liturgical forms led to a fundamental reimagination of the crusading project: what had been an offensive enterprise to liberate the Holy Land through penitential pilgrimage became a defensive effort to protect Europe against annihilation.

A book of such expansive scope and conceptual intricacy lends itself to certain weaknesses. Here, there is a significant amount of repetition across chapters, as Gaposchkin retreads similar logical and evidentiary pathways in order to pursue different investigative ends. Chapter 2, in any case, may have benefitted from being condensed and collapsed into chapter 1, whose framework it substantially rehearses. Additionally, several discussions appear to be out of place, e.g. chapter 6 makes a case for the influence of Clement V's 1309 encyclical, whereas its reception is discussed in chapter 7; the criticism of why liturgical performance, a routine part of all medieval warfare, was distinctive when performed on the First Crusade ought to have been addressed at the beginning of chapter 3, not its end and then in chapter 4. Finally, although Gaposchkin claims that her work supports the traditionalist view of crusading, i.e. Holy Land crusading was categorically distinct, her acknowledgment that “Jerusalem” was a fundamentally mobile concept in devotional contexts suggests that medieval crusading efforts beyond the Levant may still have influenced the development of the liturgy; such avenues of inquiry remain open for crusading pluralists. At any rate, these are minor criticisms. This is a monumental work deserving the attention of every medievalist.