Chapter 5
Holy war

Christian holy war, although a conceptual oxymoron, has occupied a central place in the culture of Christianity. Crusading represented merely one expression of this warrior tradition. Urban II did not invent Christian holy wars in 1095; neither did they cease with the demise of the Crusades; nor were the Crusades the only manifestation of medieval religious violence. However, the Crusades have appeared almost uniquely disreputable because of the apparent diametric and exultant reversal of the teaching of Christ and the appropriation of the language of spiritual struggle and the doctrine of peace for the promotion of war, exquisitely demonstrated in the ubiquitous use of the image of the cross. In the New Testament seemingly the ultimate symbol of Christ’s explicit refusal to fight or even resist in the face of death; in the hands of crusade propagandists the cross became a sign of obedience through the physical sacrifice of martial combat, a war banner, an icon of military victory through faith, the mark of those, in the words of a charter of one departing crusader in 1096, who fought ‘for God against pagans and Saracens’ and saw themselves as ‘milites Christi’, warriors or knights of Christ. ‘If any man will come after me, let him deny himself and take up his cross, and follow me’ (Matthew 16:24) appears an incredible battle-cry in the context of Christ’s words in Gethsemane (Matthew 26:52–4): ‘Put up again thy sword . . . all they that take the sword shall perish with the sword.’

This transformation can be illustrated startlingly in the writings of Bernard of Clairvaux (d.1153), chief propagandist and recruiting agent for the Second Crusade, one of the most influential interpreters of Christian spirituality of the entire Middle Ages. As if to counter directly those who condemned the church’s advocacy of holy war as unchristian, Bernard took New Testament passages and radically reinterpreted them. The Epistles of St Paul used military metaphor to emphasize the revolutionary nature of the new faith in contrast to the Roman world dominated by religiously sanctioned military systems: ‘We do not war after the flesh: for the weapons of our warfare are not carnal’ (II Corinthians: 3–4). In the Epistle to the Ephesians Paul descants on this spiritual military theme:

Put on the whole armour of God, that ye may be able to stand against the wiles of the devil. For we wrestle not against flesh and blood . . . Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness, and your feet shod with the preparation of the gospel of peace . . . taking the shield of faith . . . and take the helmet of salvation, and the sword of the spirit, which is the word of God.

(Ephesians 6:11–17)

Bernard redirects Paul in his tract welcoming the founding of the Templars, ‘a new sort of knighthood . . . fighting indefatigably a double fight against flesh and blood as well as against the immaterial forces of evil in the skies’; ‘the knight who puts the breastplate of faith on his soul in the same way as he puts a breastplate of iron on his body is truly intrepid and safe from everything . . . so forward in safety, knights, and with undaunted souls drive off the enemies of the Cross of Christ’. While not entirely new – similar transmutations of Paul’s spiritual armour date back to the 8th century at least – the volte face seems complete.

Scripture and Classical theory

The ideology of crusading may thus appear casuistic in its interpretation of Scripture, if not downright mendacious. Yet the contradiction of holy war in pursuit of the doctrines of peace and forgiveness boasted long pedigrees. While remaining a utopian model, the behaviour and circumstances of the Early Church soon ceased to reflect the idealism or experiences of Christianity. Although Biblical authority remained one of the cornerstones of belief, literalism proved intellectually and culturally untenable and Christianity evolved only indirectly as a Scriptural faith. The foundation texts of the Old and New Testaments needed translation, literally and conceptually, to nurture accessible and sustainable institutions of thought and observance in a context of the lives of active believers within a temporal church. The works of the so-called Church Fathers (notably Origen of Alexandria, Ambrose of Milan, Augustine of Hippo, and Pope Gregory I) found ways of reconciling the purist doctrine of the Beatitudes with the Graeco-Roman world. A mass of apocryphal scripture, imitative hagiography, legends, relic cults, and lengthening tradition expressed, informed, and developed popular belief, while ecclesiastical and political authorities codified articles of faith, such as the Nicene Creed (325). The church’s teaching on war exemplified this process.

The charity texts of the New Testament insisting on forgiveness were interpreted as applicable only to private persons not the behaviour of public authorities, to whom, both Gospel and Pauline texts could be marshalled to show, obedience was due. In Jerome’s Latin version of the Bible, the Vulgate (c.405), which became the standard text in the medieval west, the exclusive word for enemy in the New Testament is inimicus, a personal enemy, not hostis, a public enemy. Paul, conceding that ‘kings and those in authority’ protect the faithful in ‘a quiet and peaceable life’, sanctioned public violence to police a sinful world. For those justifying religious war, the Old Testament supplied rich pickings. In contrast to modern Christians not of Biblical fundamentalist persuasion, the medieval church placed considerable importance on the Old Testament for its apparent historicity, its moral stories, its prophecies, and its prefiguring of the New Covenant, as in the 13th-century stained glass windows in the nave of Chartres Cathedral where Old Testament scenes are coupled by their exegetical equivalents from the New. Bible stories operated essentially on two levels (although medieval exegetes distinguished as many as four): literal and divine truth. In the Old Testament the Chosen People of the Israelites fight battles for their faith and their God, who commands violence, protects his loyal warriors, and is Himself ‘a man of war’ (Exodus 15:3). Not only does God intervene directly, but He instructs His agents to kill: Moses enlisting the Levites to slaughter the followers of the Golden Calf (Exodus 32:26–8); God instructing Saul to annihilate the Amalekites ‘men and women, infant and suckling’ (I Samuel 15:3). Warrior heroes adorn the Scriptural landscape – Joshua, Gideon, David. In the Books of the Maccabees, recording the battles of Jews against the rule of Hellenic Seleucids and their Jewish allies in the 2nd century BC, butchery and mutilation are praised as the work of God through His followers, whose weapons are blessed and who meet their enemies with hymns and prayers. ‘So, fighting with their hands and praying to God in their hearts, they laid low no less than thirty-five thousand and were greatly gladdened by God’s manifestation’ (II Maccabees 15:27–8). Many Old Testament texts, especially those concerning Jerusalem (for example Psalm 79: ‘O God, the heathen are come into thine inheritance; thy holy temple have they defiled; they have laid Jerusalem on heaps’, were easily incorporated into crusading apologetics and polemic, but nowhere was the idiom of crusading more apparent than in the Books of the Maccabees.

Of course, stories regarded by some as authorizing legitimate or even religious warfare could be interpreted by others as prefiguring Christian spiritual struggle, the sense of St Paul as well as many medieval commentators, or consigned to the Old Covenant not the New Dispensation. Trickier for Christian pacifists were the apocalyptic passages in the New Testament. The Revelation of St John described a violent Last Judgement when celestial armies followed ‘The Word of God’ and judged, made war, smote nations, and trod ‘the winepress of the fierceness and wrath of Almighty God’ (Revelation 19:11–15). It is no coincidence that one of the most famous and vivid eyewitness descriptions of the massacre in Jerusalem on 15 July 1099 quoted verbatim Revelation 14:20: ‘And the winepress was trodden without the city, and blood came out of the winepress, even unto the horses’ bridles.’ Apart from examples of godly mayhem, the Bible imposed a generally providential and specifically prophetic dimension on Christian holy war that is hard to underestimate. If wars are seen as God’s will, then they act as part of His scheme, either in imitation of past religious wars or, more potently, as fulfilment of Biblical prophecy, a fixation as appealing to crusaders as later to Oliver Cromwell.

Christian holy war, therefore, derived from the Bible its essential elements: Divine command; identification with the Israelites, God’s chosen; and a sense of acting in events leading towards the Apocalypse. The historical and emotional vision of the holy warrior encompassed the temporal and supernatural. The fighting was only too material but the purpose was transcendent. However, it is difficult to see how even the most bellicose interpretation of Scripture alone could have produced such an acceptance and later promotion of warfare without the need to reconcile Christianity with the Roman state in the 4th and 5h centuries ad. While the Bible bore witness to the Law of God, old and new, the Helleno-Roman tradition had developed laws of man on which Christian writers drew to devise a new theoretical justification for war. Aristotle, in the 4th century BC, had coined the phrase ‘just war’ to describe war conducted by the state ‘for the sake of peace’ (Politics I:8 and VII:14). To this idea of a just end, Roman law added the just cause consequent on one party breaking an agreement (pax, peace, derived from the Latin pangere, meaning to enter into a contract) or injuring the other. Just war could therefore be waged for defence, recovery of rightful property, or punishment provided this wassanctioned by legitimate authority, that is the state. Cicero argued for right conduct – virtue or courage – in fighting a just war. Consequently, all Rome’s external wars against hostes, public enemies, especially barbarians, were regarded as just wars.

With the 4th-century recognition of Christianity as the official religion of the empire, Christians shouldered duties as good citizens, encouraged to fight in just wars for the defence of the Christian empire. For the Roman state, religious enemies joined temporal ones as legitimate targets for war: pagan barbarians and religious heretics within the empire who could be equated with traitors. However, no sooner had Christian writers such as Ambrose of Milan (d.397) integrated Christian acceptance of war based on the model of the Israelites with the responsibilities and ideology of Roman citizenship than the political collapse of the empire in the west threatened to undermine the whole theoretical basis of Christian just war. This conundrum was resolved by Augustine of Hippo (d.430) who, in passages scattered unsystematically through his writings, combined Classical and Biblical ideas of holy and just war to produce general principles independent of the Christian/Roman Empire. To the Helleno-Roman legal idea of right causes and ends, Augustine added a Christian interpretation of moral virtue to right intent and authority. From his diffuse comments three familiar essentials emerged: just cause, defined as defensive or to recover rightful possession; legitimate authority; right intent by participants. Thus war, inherently sinful, could promote righteousness. These attributes form the basis of classic Christian just war theory, as presented, for example, by Thomas Aquinas (1225–74). But Augustine did not regard violence as an ideal, preferring the world of the spirit to that of the flesh. His justification of war looked to the wars of the Old Testament: ‘the commandment forbidding killing was not broken by those who have waged war on the authority of God.’ Augustine was implicitly moving the justification of violence from lawbooks to liturgies, from the secular to the religious. However, his lack of definition in merging holy and just war, extended in a number of pseudo-Augustinian texts and commentaries, produced a convenient conceptual plasticity that characterized the development of Christian attitudes to war over the subsequent millennium and more. The language of the bellum justum became current, while what was often described came closer to bellum sacrum. This fusion of ideas might conveniently be called religious war, wars conducted for and by the Church, sharing features of holy and just war, in a protean blend that allowed war to become valid as an expression of Christian vocation second only to monasticism itself.

A just war was not necessarily a holy war, although all holy wars were, per se, just. While holy war depended on God’s will, constituted a religious act, was directed by clergy or divinely sanctioned rulers, and offered spiritual rewards, just war formed a legal category justified by secular necessity, conduct and aim, attracting temporal benefits. The fusion of the two became characteristic of later Christian formulations. Where Rome survived, in Byzantium, the eastern empire of Constantinople, the coterminous relation of Church and State rendered all public war in some sense holy, in defence of religion, approved by the Church. However, Byzantine warfare remained a secular activity, for all its Divine sanction, not, as it became in late 11th-century western Europe, a penitential act of religious votaries. Elsewhere in Christendom, while the ideals of pacifism remained fiercely defended by the monastic movement and its ideal of the contemplative life, Christians and their Church had to confront new secular attitudes to warfare consequent on political domination by a Christianized Germanic military elite and new external threats from non-Christians.

New Defenders of the Faith in the early Middle Ages

War occupied a central place in the culture as well as politics of the Germanic successor states to the Roman Empire from the 5th century. The great German historian of the origins of the crusading mentality, Carl Erdmann, argued that for the new rulers of the west war provided ‘a form of moral action, a higher type of life than peace’. Heavily engaged in converting these warlords, the Christian Church necessarily had to recognize their values, not least because, with the collapse of Roman civil institutions, economic and social order revolved around the fiscal and human organization of plunder, tribute, and dependent bands of warriors held together by kinship and lordship. Their Gods were tribal deliverers of earthly victory and reward. It has been said that the early medieval army, the exercitus, assumed a role as the pivotal public institution in and through which operated justice, patronage, political discipline, diplomacy, and ceremonies of communal identity, usually with the imprimatur of religion, pagan or Christian. The effect of the conversion of these Germanic peoples worked in two directions: the Christianizing of their warrior ethic and the militarizing of the Church.

Contemporary descriptions of the conversion and early Christian kings of the new political order are peppered with martial heroes in the style of Constantine himself, such as Clovis the Frank (d.511) or Oswald of Northumbria (d.644). Conversely, Christian evangelists and holy men were depicted exercising physical aggression as God’s agents in the style of the Old Testament Moses. Unsurprisingly, Germanic warrior values infected the language of the faith being conveyed, even if only in the seedbed of metaphor. In the 8th-century Anglo-Saxon Dream of the Rood, Christ is depicted as ‘the young warrior’, ‘the Lord of Victories’; death on the cross as a battle, with Heaven a sort of Valhalla. A 9th-century Old German poetic version of the Gospel story shows Christ as a lord of men, ‘a generous mead-giver’, his disciples a war band travelling in warships, Peter ‘the mighty noble swordsman’. While fiercely resisted by many academics and monks, this militarized mentality received the powerful confirmation of events.

The historical as well as literary type of the early medieval warrior was Charlemagne (d.814), king of the Franks and, from 800, emperor of the west, his wars against pagan Saxons and Avars portrayed by eulogists, official propaganda, and the Church in terms of the Faith. Given that forcible conversion acted as part of his policy of subduing the Saxons, the image reflected actual war aims. Through prayers, blessings of warriors and their arms, liturgies, and differential scales of penance, the Frankish Church elevated these conflicts into holy wars. More widely, the Church presided over a political culture in which the figure of the armed warrior increasingly received religious as well as social approbation, a development sharply illustrated in contemporary saints’ lives. Warfare came to be recognized as possessing positive moral as well as political value. As with the Roman Empire it professed to be reviving, in the Carolingian Empire of the 8th and 9th centuries, public war was ipso facto just and sanctioned by God. This became even more apparent from the mid-9th century when, with the disintegration of Carolingian power, western Europe was beset by new external attacks from Muslims, Vikings, and Magyars which lent an urgent, dynamic quality to the practice as well as theory of Christian warfare. Political and religious survival became synonymous as a concept of a religious community, Christendom (Christianitas), replaced the disintegrating political community of the Frankish Empire. Confronted by Muslims threatening Rome itself, Pope John VIII (872–82) offered penitential indulgences remitting the penalties of sin to those who fought and died fighting. His predecessor Leo IV (847–55) had similarly promised salvation to warriors against the infidels. The identification of religion and war surfaced across western Europe. Monkish propagandists invariably called the Danish enemies of Alfred, king of Wessex (871–99), pagans; his commanders decorated their swords with Christian motifs and their battles were accompanied by prayers and alms. A Frankish monastic annalist similarly described Danish attacks as an ‘affront not to us but to Him who is all powerful’. Such explicit Christian militancy, designed to inspire resistance and confirm communal solidarity, enlisted some unlikely recruits. Even St Benedict (d.c.550), founder of the main contemplative monastic movement of western Europe, was depicted in the later 9th century as fighting the Vikings ‘with his left hand directing and shielding the cavalry and with his right killing many enemies with his staff’.

This militarization of western Christian culture that long predated the Crusades should not be exaggerated. The monastic ideal persisted, Aelfric of Cerne, abbot of Eynsham, at the end of the 10th century insisting on the monks’ vocation as ‘God’s champions in the spiritual battle, who fight with prayers not swords; it is they who are the soldiers of Christ’. Although examples of warrior saints, or saints who were once warriors, proliferated in the 10th and 11th centuries, the moral dangers of fighting continued to be recognized. However, at least from Carolingian penitential observances onwards, churchmen drew a distinction between killing in a public conflict authorized by a legitimate secular (or religious) authority, bellum, and illicit private war, sometimes distinguished by the wordguerra, those fighting in the former receiving lighter penances for their killing than those engaged in the latter. Still, the actual act of combat remained sinful; despite fighting under a papal banner in a cause considered by their clergy to be just, William of Normandy’s followers in 1066 were forced to perform modest penance for the slaughter they inflicted at the Battle of Hastings. The late 11th-century revolution lay particularly in the settled transformation of the actual violence, rather than its purpose, scale, or intent, into a penitential act.

The origins of the crusade in the 11th century

The changing articulation of the long-held acceptance of legitimate religious war that combined elements of the Helleno-Roman and Biblical traditions was fashioned as much by political circumstance as by theology. Renewed attention to Augustinian theory from the late 11th century came in response, not as an inspiration, to greater ecclesiastical militancy. Secular influences included the problem of public authority and social order after the collapse of Charlemagne’s empire in the 9th and 10th centuries; the altered terms of the frontier conflicts with Islam, with Christians from the 10th century increasingly on the offensive; and a greater ideological and political stridency of the papacy. Behind all of these lay the cultural identity between lay and clerical rulers who belonged to the same propertied aristocracy. Bishops took the field in battles, sometimes in armour, often at the head of their own military entourage, occasionally engaging in physical combat. Equally, many of the most vicious secular lords were patrons of monasteries, went on exhausting and dangerous pilgrimages, and died in monastic habits as associate members of religious orders.

This cultural intimacy, a feature of the whole of the early Middle Ages, took on greater significance in the development of holy war as the apparatus of civil authority devolved downwards nearer to the human and material resources on which all power depended as public authority was usurped by private lordships. Although less anarchic than once imagined, new social conditions by the end of the 10th century encouraged violence as a means of settling disputes as well as achieving more larcenous or territorial ambitions. This fragmentation of power in western Francia (more or less the region from the Rhine to the Pyrenees, later the cradle of the crusade), by negating kingship, resulted in a deficit of effective public arbitration or political discipline. In such circumstances, to secure protection and status, many churchmen deliberately promoted the responsibility of men of violence to protect the church. To achieve this, the activities of the warrior had to receive explicit praise not just on the level of public wars against pagans and heretics. This acceptance of the need for warlike protectors can be traced in saints’ lives and monastic chronicles that exhibit a characteristic schizophrenia when tackling the gilded ‘faithful to God’ who were also self-serving killers, the contrast later favoured by crusade apologetics between militia and malitia.

The symbiotic relationship of church and local military aristocracies found concrete expression in formal proceedings organized by local or regional clergy to ensure the physical protection and policing of their property. From the late 10th century, across the duchy of Aquitaine and Burgundy, later spreading to northern France and the Rhineland, church councils were convened that proclaimed the Peace of God with arms bearers swearing, in public ceremonies, to protect those outside the military classes, effectively churchmen and their property. From the 1020s specific periods of weeks or months were designated as Truces of God, during which all such violence should cease, again to be policed by sworn warriors. Although some have challenged the direct influence of the Peace and Truce of God on the origins of crusading, the Council of Clermont in 1095 authorized a Peace of God at the same time as initiating the Jerusalem campaign. These local churchmen, often in concert with regional counts, were not simply condemning illicit attacks on their interests but approving, indeed promoting, violence to prevent them. From being called upon to bless wars for causes sacred and profane, the Church now assumed the roles of author and director, its warriors that of religious votaries.

This trend received strong impetus from the 1050s through the concern of successive popes with the idea and practice of holy war as a weapon to establish the independence of the Church from lay control, contest the authority of the German emperor, ensure the political autonomy of the Roman see, and recover the lost lands of Christendom. The moral standing of those who fought for the papal agenda became an important aspect of the general policy, both in the need to attract support and to assert the uniqueness of the cause. In 1053, Leo IX (1048–54), leading an army in person against the Normans of southern Italy, offered German troops remission of penance and absolution for their sins, a tradition followed by his successors. Papal banners were awarded to the Norman invaders of Muslim Sicily (1060) and England (1066) and to the Milanese Patarines, street gangs contesting control of the city against the imperialists in the 1060s and 1070s in a struggle elevated in papal rhetoric to a bellum Dei, a war of God. To combat the ecclesiastical power of Emperor Henry IV (1056–1106) in Germany and his political ambitions in Italy, Pope Gregory VII (1073–85), one of whose favourite quotations was ‘Cursed be he that keepeth back his sword from blood’ (Jeremiah 48:10), sought to recruit his own army, the militia Sancti Petri. Papal apologists began to write of an ordo pugnatorum, an order of warriors, who fought ‘for their salvation and the common good’, very much the target audience identified by Urban II in 1095. By the end of his pontificate, Gregory’s rhetoric transformed the status of his warriors, comparing their service in defence of the Church as an imitation of Christ’s suffering against ‘those who are the enemies of the cross of Christ’. War had become an act of penance. An abortive project for an eastern expedition in 1074 proposed by Gregory VII to aid Byzantium evinced many elements later deployed by Urban II. Gregory referred to the mandate of God and example of Christ; the goal of Jerusalem; help for the eastern church as an act of charity; and the offer of ‘eternal reward’. All that was missing were the vow, the cross, and the associated privileges.

The papacy’s advocacy of a more embracive theory and practice of holy war mirrored a wider transformation in the religious life of 11th- and 12th-century western Europe from an essentially local and cultish faith, with regional saints and liturgies, to one more regulated by pastoral uniformity, canon law, and international ecclesiastical discipline. Devotion to saints and their relics became increasingly universal, with a concurrent emphasis on the historicity of the gospel stories, the humanity of Christ, and the cult of the Virgin Mary, which began to dominate church dedications across Christendom. Coupled with the development of elaborate Easter rituals featuring Christ’s agonies for Man’s Redemption and an increased concentration on the Christocentric aspects of the Mass (for example the Real Presence, the use of crucifixes, and so on), the image of the Holy Land, of Christ’s suffering, and of Christian obligation penetrated far beyond the reach of papal rhetoric. The increased popularity of international or Biblical saints reflected anxiety over salvation that the new conception of war addressed directly. The perceived celestial clout of saints had long been a factor in their level of popularity, leading to the strenuous promotion of local shrines by their guardians and the reciprocal gifts of alms and property from the faithful. Penance emerged as a most urgent issue for laymen because the methods for laymen to attain remission of the penalties of sin remained rudimentary. The problem may have appeared especially acute for lay arms bearers, paradoxically because their function had come under such close ecclesiastical scrutiny and acceptance. If monastic charters and chronicles can be believed, penitential war answered a genuine craving to expiate sin. The First Crusade drew excited praise as ‘a new way of salvation’ for the military classes. Apart from donations to monasteries so that monks could pray for their souls, increasingly laymen in the 11th century found pilgrimages promoted by the clergy as a means to expiate sin, with Jerusalem prominent in practice and imagination. Psychologically, if not legally, religious wars, especially against distant targets such as infidels, lent themselves to identification with pilgrimages as both were conducted for God and involved journeys, always a powerful spiritual metaphor. Gregory VII’s reference to going on to the Holy Sepulchre in his 1074 plan suggested a fusion of war (to help eastern Christians) and pilgrimage, a connection repeated by Urban II in granting indulgences in 1089 to those colonizing Tarragona on the Muslim frontier in Spain. The Pisans who attacked Mahdia in Tunisia in 1087 fitted in a pilgrimage to Rome. The concept of an armed pilgrimage has frequently been identified as the key to explain the novel appeal of the expedition preached by Urban II, offering a familiar frame for a new secular act of penance.

However, there remain problems with this interpretation of Urban’s scheme. On the one hand, armed pilgrimages to Jerusalem predated 1095; at least one group of armed German pilgrims in 1064 also wore crosses. On the other, in his correspondence in 1095–6, Urban avoided any explicit reference to pilgrimage, talking instead of a military expedition (expeditio) to ‘restrain the savagery of the Saracens by their arms’. The portrayal of the Jerusalem war as a pilgrimage emerged during the recruitment process, possibly fromthe clergy who had to broadcast the message and articulate crusaders’ motives when compiling records of their fundraising. Urban’s penitential journey could best be understood canonically as a pilgrimage, with the emphasis on its spiritual quality. The pope’s language and many charters were less ambivalent, calling for the violent expulsion of the infidel from the holy places ‘to fight for God against pagans and Saracens’, as one Burgundian charter put it. Images of infidel atrocity, brutality, and force permeate Urban’s letters stressing the legitimacy of the war, both in terms of right authority (the pope’s) and right intent (‘devotion alone’) to counter any unease at such a blatant call to arms. Early responses, such as the Rhineland massacres, indicated the centrality of violence in the enterprise. The current historiographical emphasis on the pious motives of crusaders can obscure the direct relationship between piety and violence that influential elements in the Church had willingly encouraged, recognizing them as mutually engaged mentalities: service to Christ as physical vengeance; the dangers of campaigning as the imitation of Christ’s sufferings; war as an act of charity. In addressing a violent society, Urban, a French aristocrat as well as a former monk, did not compromise with its values: he and his ideology were part of it. Charters provide as much evidence for martial as for pious responses to the First Crusade. Even the letters of crusaders on the march are sparing in their association with pilgrimage, although by 1099 and after the link became ubiquitous. As a holy war, transcendent, spiritual, emotive, the Jerusalem journey was rendered special by the plenary indulgences and the elevated goal of the Holy Sepulchre. Given its stated objective – Jerusalem – an armed pilgrimage may have seemed an appropriate analogy to clerical observers, as nervous of unashamed innovation as of unfettered violence. Only by virtue of the Jerusalem journey becoming a habit did it require fitting into the existing structure of devotional exercises. Urban seemed to have conceived of the operation as unique and unrepeatable; he preached it openly as holy war not armed pilgrimage, a new vision of a very old idea.

Western Christianity held no monopoly on holy war. The Byzantine Empire retained the Roman unity of Church and State that allowed all State conflicts to attract ecclesiastical blessing. Greek emperors portrayed themselves as champions of the Church, especially when fighting pagan Slavs in Bulgaria or Muslims in the Near East. While never interfering with practical diplomacy, Byzantine holy war rhetoric could adopt motifs familiar in the west, as in 975 when John I Tzimisces (969–76) invaded Syria and northern Palestine and may have dangled the prospect, if only in his propaganda, of the reconquest of the holy sites of Jerusalem. Byzantine holy war asserted an integral dimension of public policy, while never attracting the association of violence as penance. It lacked the novelty or the political and spiritual autonomous dynamism of its western counterpart, hence the slightly jaded, condescending superiority expressed by Greek observers, such as Anna Comnena (1083–1153), daughter and biographer of Emperor Alexius I, at the enthusiasm of the early crusaders.

By contrast, the Muslim jihad has regularly and lazily been compared with western Christian holy war and the crusade. Unlike the crusade, under Islamic law derived from the Koran, jihad, struggle, is enjoined on all members of the Muslim community. Unlike the crusade, according to classical Islamic theory traditionally dating from the 7th and 8th centuries but possibly later, the jihad takes two forms: the greater (al-jihad al-akbar), the internal struggle to achieve personal purity, a concept not too far removed from St Paul’s martial metaphors for the spiritual life; and the lesser (al-jihad al-asghar), the military struggle against infidels. Both were obligatory on able-bodied Muslims, but while the former existed as a permanent individual obligation, the lesser jihad could be interpreted as a communal activity. Unlike the crusade and Christian holy war, to which the Islamic jihad appears to have owed nothing (and vice versa), jihad was fundamental to the Muslim faith, a sixth pillar. The essence of jihad remained as a spiritual exercise. Its operation depended on context. In the Muslim lands, the Dar al-Islam (House of Islam), a grudging religious tolerance was guaranteed by early Islamic texts, at least for the People of the Book, Jews and Christians; instead of persecution or enforced conversion they more profitably paid a special poll tax, the jizya. Pace modern sentimentalists and apologists, there existed little generosity in such tolerance, merely pragmatism. By contrast, beyond Islamic rule, in the Dar al-harb (House of War), non-Muslim political structures and individuals were open to attack as, in Koranic theory, the whole world must recognize or embrace Islam (which means surrender, that is to God) through conversion or subjugation. As with Christian holy war, circumstances determined themujahiddin nature and conduct of jihad as much as theory. In frontier areas, such as in Spain or Anatolia, groups of ghazi or mujahiddin holy warriors, flourished as mercenaries, in tribal groups or, as in the military ribats of Muslim Spain, in quasi-monastic communities. With the zeal of new converts, the Seljuk Turks gave the jihad a new impetus along the border with Byzantium, but for generations before the spiritual revival of the 12th century there was little attention paid within the Muslim Near East to martial as opposed to spiritual jihad. It remains a moot point whether the advent of the crusaders or fundamentalist revivalism originating further east excited the new military fanaticism espoused by the 12th-century Zengids and Ayyubids. In later periods, the dominance of the Ottomans and an uncertainty, which persists, about the existence of a genuine Dar al-Islam, complicated attitudes to jihad. However, the genesis, nature, and implementation of jihad cannot be equated directly with those of the crusade; it operated and operates in a very different ideological and religious value system, with different inspirations and justifications, even if its power to inspire and its physical consequences can be equally bloody for its victims and obsessive for its initiates.

Holy war, crusade, and Christian society after 1095

In medieval Christendom the malleable contingency of the crusade in concept and practice ensured its popularity and longevity. The defined uniqueness of the Jerusalem journey allowed its essentials – the vow, the cross, plenary indulgence, and temporal privileges – to be transferred to other theatres of religious and ecclesiastical conflict on the principle of equivalence: Spain, the Baltic, internal enemies of the papacy, and heretics. The success of 1099 silenced most critics as well as establishing later conduct. Holy war, commanded by God, earning spiritual reward, continued to provide an important weapon in the papacy’s armoury. To signal especial gravity (or papal favour), a comparison with the Jerusalem war could be drawn. However, the Jerusalem model exerted only limited influence on canon law and in no sense became the universal or exclusive form of Christian holy war. Its most profound and lasting innovation came with the 12th- and 13th-century creations of military religious orders, embodiments of the oxymoronic nature of Christian holy war, whose members became, uniquely in Christian society, permanent, professional holy warriors. As a holy war, the crusade fell outside the categories for just war explored in detail in the Decretum (first redaction c.1139, enlarged edition by 1158) traditionally ascribed to Gratian of Bologna, its legal implications deriving from its associated privileges standing apart from both the academic attempts to define and limit warfare and the experience of battles of the cross. Away from the Curia, especially in frontier regions on Christendom’s northern and southern borders, where traditions of intercommunal and inter-faith conflicts readily merged, holy war offered a natural recourse, its acceptability parallel to that of crusading, deriving from similar cultural impulses, but not necessarily narrowly determined by the Jerusalem war. The Danish writer Saxo Grammaticus (c.1200) carefully cast his heroes in the Danish wars against their neighbours in terms both specifically of crusade and more generally of holy war. For his employer Archbishop Absalom of Lund (d.1202), it was ‘no less religious to repulse the enemies of public faith than to uphold its ceremonies’; he was content to make ‘an offering to God not of prayers but of arms’. Similarly in Spain, the granting of formal crusading privileges acted within a context of growing identification of the Reconquista with holy war; as early as c.1115, the patron saint, the Apostle St James, was described in a northern Spanish chronicle as ‘the knight of Christ’.

While the long tradition of holy war continued to supply the emotional intensity for a range of Christian warfare, the Jerusalem war and its derivatives did not escape the scrutiny of lawyers and academics who increasingly sought to integrate the crusade into a comprehensive canonical justification for violence, rather than, as the appeals for the First and Second Crusades implied, rely simply on Divine mandate and the individual devotional standards of participants. Until the 13th century, and arguably beyond, the crusade remained an ill-defined legal concept. Where Christian war coincided with classical just war categories, as with the defence of Outremer (‘the heritage of Christ’), national defence, or the suppression of heretics, fusion with classical and Augustinian just war appeared obvious. In the temporal sphere, it also became necessary, in clerical eyes, to produce a detailed set of legal conditions determining the validity of warfare as crusade targets diversified around 1200, at the same time as secular attitudes to violence coalesced into social norms manifested in the cult of ‘chivalry’. The more respectable war became, the more urgent the need for the Church to define what was and what was not sinful about it, especially as Innocent III and his successors transformed crusading into a universal Christian obligation involving all society. Thus, as an aspect of the pastoral reformation within the western church, holy war, not specifically crusading, became tempered by theories of the just war, so much so that the mid-13th-century canonist Hostiensis came close to defining a crusade simply as a papally authorized just war. By the end of the 14th century, Honoré Bonet (or Bouvet) in the Tree of Battles (1387) answered the question ‘By what law or on what ground can war be made against the Saracens?’ with wholly traditional arguments based solely on a just cause – occupation of Christian land or rebellion against Christian rule, and papal authority. In this fashion, the crusade had become reintegrated into a characteristic western European concept of legitimate violence, catching its inspiration from holy war and its legality, rules, and restraints, if any, from classical just war theory. As such the language, motifs, and institutions of crusading penetrated into conflicts where no formal apparatus of crusading existed, for example the adoption of crosses by national armies, such as the Danes c.1200 or the English in the 14th century. So pervasive were the symbols and habits of crusading that they could be turned to any political conflict that boasted an ideological tinge, even in the most contradictory of circumstances. Crosses were offered enemies of papal crusaders in southern Germany in 1240. During his rising against what he saw as the misgovernment of Henry III of England in 1263–5, Simon de Montfort’s rebels donned the white crusader crosses of the English kings, traditional since the Third Crusade, to fight royalist crusaders. The prominence lent holy war by the Crusades contributed to the familiar western European habit of warring parties of more or less whatever description invoking self-righteous religiosity in support of their cause, a habit, exported to European settlements around the world from the 17th century, that remains current in the 21st century.

Whatever its legal frame, crusading operated as the ultimate manifestation of conviction politics in medieval western Europe, entrenching a narrow cultural and religious exclusivity. When crusaders sacked Lisbon in October 1147, they murdered the local Mozarab Christian bishop alongside his fellow Arabic-speaking Muslim neighbours before happily installing an Englishman, Gilbert of Hastings, as the new bishop. The failure of the Latin Church hierarchy easily to cooperate or combine with higher ranks of the eastern churches in Outremer or, later, Greece was notorious. Although inherent in all holy wars, demonization of opponents reached extreme levels in crusading rhetoric, reflecting both a literary genre and a worldview conducive to a siege mentality, a form of cultural paranoia so often the underbelly of cultural assertiveness. Racism and intolerance of minorities were not caused by the Crusades. Indeed, both in the Baltic and Spain, legal, linguistic, cultural, and blood racism deepened in the centuries after the main conquest by warriors of the cross. Yet, in anti-Jewish pogroms and wars against heretics and dissent, crusading helped define a rancid aspect of a persecuting mentality that came as the almost inevitable concomitant of a Church bent on supremacy and uniformity to secure its pastoral ends and secular rulers eager for ideological sanction for their wars.

14. The medieval ideal of the crusader knight. An English illustration from a mid-13th-century psalter: piety and power.

As holy war addressed fundamental issues of Christian identity and, it was frequently proclaimed, Christian survival, its elements remained embedded in European society as well as providing a cutting edge in the expansion of Latin Christendom southwards, eastwards, and northwards. The habit of crusading died hard; in the 15th century crusading formulae were natural appendages for the expansion of European power down the west coast of Africa and into the eastern Atlantic, as they were in the religious wars in Bohemia as well as in defence against the Turks. In the 16th century and beyond, the Ottomans kept the images and occasionally the reality of the war of the cross alive, while the internal religious divisions in Europe ushered in a period of religious wars no less vicious in commitment and butchery than anything witnessed in previous centuries. Some historians would argue that the period of the Crusades defined Christianity’s affection for holy war – far from it. The Crusades formed only one articulation of Christian holy war, whose origins long pre-dated 1095 and whose legacy refused to fade. Even in a supposedly more secular age, self-righteous, ideologically justified warfare persists. The modern world has embraced, variously with horror and energy, ideological, religious, and pseudo-religious violence as well as racist, nationalist, and anti-Semitic pogroms on an industrial scale, all in the context of justifying moralities. The moral high ground of the 21st century, whether shaded by the banners of religion, reason, capitalism, or freedom, still lies pitted with the rank shell-holes of holy war.