As the author remarks, the story of the First Crusade is remarkable. And one must say, Jay Rubenstein tells it very well. The basic facts are striking: some 100,000 people, representing all classes in medieval European society, gathered into groups in France, Italy, and Germany. In 1096 these groups set off for Jerusalem, nearly 2,000 miles away. Following three years of struggle, in which many died in fighting or from hunger and exhaustion, while others were persuaded to turn back, some portion of the original number conquered the Holy City. Having killed all the residents, the victors turned Jerusalem into a European outpost—an accomplishment that held, more or less, until the armies of Saladin restored the city to Muslim control in 1187.

How might one explain these facts? As Rubenstein notes, many accounts focus on military history or on the political goals of significant actors—Pope Urban II sought to foster Christian unity; the Byzantine Emperor Alexius II hoped the influx of European arms might help him to recover territory lost to the Muslim armies.

Such “realistic” accounts do not catch the unique character of the adventure, however. As Rubenstein argues,

It is this judgment that gives the sense of Rubenstein's title. The armies of the First Crusade imagined they were instruments of God, characters in a story that would culminate in the establishment of God's kingdom.

I should say at the outset that Rubenstein's book will work well in undergraduate or graduate courses. That said, it is worth pressing several questions likely to occur to scholars. I'll mention two of these: the first reflecting Rubenstein's expansive use of the concept “apocalyptic”; the second regarding the claim that the Crusade constituted a “new type of war . . . with its own set of rules” (199).

With respect to the first, Rubenstein makes the terminology apply to a wide range of behaviors. From the standpoint of the history of religions, a number of these do not require the category “apocalypse.” For example, the notion that God fights for or with the faithful, or that groups of people identify particular leaders with figures like Moses recur in numerous contexts. They need not correlate with the motifs familiar from texts like Mark 13 or the Book of Revelation. Where Rubenstein is most interesting on such conceptual questions may be illustrated by the argument at page 120 and elsewhere, to the effect that an “apocalyptic perspective” is one in which human beings “re-create and relive some of the key moments in history.” They “enter apocalyptic time.” At some points in the narrative (45–53, for example), the tie to specifically apocalyptic texts and themes seems clear. But people can and do read current events in the light of, say, the Exodus, or even invoke eschatological tropes without quite moving all the way to the Apocalypse.

The characterization of the First Crusade as “new type of war” is an extension of a recurring theme in Rubenstein's book that “holy war” lends itself to violations of the ordinary rules by which groups of people regulate armed conflict. In the case at hand, the record is filled with examples: the killing of civilians, mutilation of corpses, even cannibalism. As Rubenstein notes, prohibitions of such behaviors in fighting between Christians were well articulated (if not always observed) by the time of the Crusades. What, then explains the slaughter of those living in Antioch, or ultimately at Jerusalem? With respect to Antioch, Rubenstein ties Crusader behavior to Deuteronomy 20, suggesting that those fighting understood these and other cities as a “special Christian inheritance” (Dt. 20:16-18 directs the people of Israel to “annihilate” those living in the towns which “the Lord your God is giving you as an inheritance, as distinguished from the towns “that are very far from you” in 20:10-15). In the case of Jerusalem, he returns to the notion of apocalypse, this time in particular to Rev. 14:20 and its vision of the blood that flows from “the wine press of God's wrath”; such images are coupled with the notion that the Muslims living in the city should be considered enemies of God. One issue here is that the behavior is not particularly “new” (not to put too fine a point on it, such would be indicated by Rubenstein's invocation of biblical texts). As James Turner Johnson has shown in Just War Tradition and the Restraint of War (Princeton, N.J.: Princeton University Press, 1981) and other works, norms constructed to regulate war among people within a particular community often do not apply to fighting between religiously or culturally distinct groups. The issue, it seems, has to do with the kind of norms that ought to apply across cultural lines. In this regard, it is interesting that some of Rubenstein's sources express a certain double-mindedness about the behaviors in question. They are justified, or perhaps those engaging in them are excused in view of the nature of the enemy, biblical precedents, and the like. Nevertheless the behaviors violate a sense of propriety regarding honorable combat; they require explanation, and at least in some cases, acts of expiation upon return to Christian society.

The concluding chapter of Armies of Heaven is entitled “The Never-Ending Apocalypse.” Here, Rubenstein touches on the import of the First Crusade for the development of Europe and the distinction between a geographic and cultural “East” and “West.” As he has it,

A fine ending, to a very interesting book.