By Andrew Latham
Between the mid-11th and late-15th centuries, an historically specific configuration of material and ideational factors gave rise to a constellation of religious wars that have come to be known as “the crusades”.
This constellation included Church-organized wars in the Holy Land, Iberia and along the Baltic frontier as well as within Latin Christendom itself. The Crusades to the Holy Land were “wars of liberation” initially launched by the Church to restore Jerusalem to Christian rule. Following the First Crusade and the establishment of the crusader principalities (the County of Edessa, the Principality of Antioch, the County of Tripoli, and the Kingdom of Jerusalem – collectively known as Outremer), these expeditions were conducted primarily to defend the Holy Places against Muslim attempts at reconquest or, following its loss in 1187 and again in 1244, to recover Jerusalem for Latin Christendom. While authorized by, and fought on behalf of, the Church these wars were prosecuted by princes, nobles and knights from every corner of Latin Christendom as well as by so-called “para-crusaders” (milites ad terminum), and members of military orders such as the Templars, Hospitallers and Teutonic Knights. They were fought primarily against a range of Muslim powers, although the Fourth Crusade ended up being waged largely against adherents to the Greek Orthodox rite. Although the idea of launching additional expeditions to liberate Jerusalem persisted for a considerable time, the Crusades to the Holy Land effectively came to an end with the fall of the last Christian stronghold in Palestine – Acre – in 1291.
The Iberian crusades were a series of military campaigns launched by the Church to liberate Christians from Muslim rule in what are now Spain and Portugal. While undertaken against the backdrop of the Reconquista, they are neither reducible to, nor synonymous with, this much broader and more complex geopolitical phenomenon. Although it came to be seen as a sanctified enterprise, the Reconquista was in large measure a “political” process of conquest, conversion and colonization that unfolded over several centuries. The Iberian crusades, on the other hand, were a series of discrete papally authorized, religiously motivated military campaigns that punctuated that centuries-long process. The Reconquista was not, in other words, an “eternal” or “perpetual” crusade such as would emerge in the Baltic region. To be sure, these two phenomena clearly exercised a reciprocal influence one another; just as clearly, however, they remained distinct expressions of the historical structure of medieval war.
Unlike the crusades in the Holy Land and Iberia, which were understood to be elements of the Church’s eschatological struggle against Islam, the Northern Crusades were “indirect missionary wars” launched by the Church to create the conditions necessary for the subsequent evangelization of the pagan Baltic region. As with their Iberian counterparts, these crusades were part of a broader phenomenon of territorial conquest and colonization – in this case, the medieval German Ostsiedlung or “settlement of the East” – but were not reducible to it. Although in this case there was a dimension of “perpetual crusade” that was not found in Spain, the Northern Crusades were nevertheless discrete campaigns punctuating the three-centuries long process of conquest and colonization that Germanized and Christianized the Baltic region. As Peter Lock has characterized argued, this process unfolded in five partly overlapping phases: the Wendish Crusades (1147-85), the Livonian and Estonian Crusades (1198-1290), the Prussian Crusades (1230-83), the Lithuanian Crusades (1280-1435), and the Novgorod Crusades (1243-15th century). While authorized by, and fought on behalf of, the Church these wars were prosecuted by Danish, Saxon, and Swedish princes as well as by military orders such as the Sword Brothers and the Teutonic Knights. They were fought primarily against a range of pagan adversaries – Wends, Livonians, Estonians, Lithuanians, Suomi, and Prussians – although some were also waged against Russian Christian schismatics (i.e. adherents to the Greek Orthodox rite). By the early 16th century, these ecclesiastical wars – always only one element of broader process of the expansion of medieval Europe – had contributed significantly to extension of the northeastern frontier of Latin Christendom and the transformation of the Baltic from a pagan mare incognita into a Latin Christian lake.
The final expression or form of religious war, however, was not directed outward against Muslims or pagans, but inward against Christians within Latin Christendom. These “internal crusades” were of two types. The first involved Church-organized wars against schismatics and heretics such as the Cathars, Hussites and Waldensians. These heterodox religious movements were seen a “a threat to Christendom, a threat, as Hostiensis put it, to Catholic unity which was in fact more dangerous than to the Holy Land.” This type of crusade was thus seen as a defensive war fought against those who threatened the Church’s spiritual authority. The second type of internal crusade involved wars launched by the papacy against temporal powers it believed threatened the Church’s political authority. Examples include Pope Innocent II’s 1135 crusade against the South Italian Normans “for the liberation of the Church” and Pope Innocent III’s 1199 crusade Markward of Anweiler who, the pope charged, was impeding the Fourth Crusade. As Riley-Smith notes, these internal crusades were always framed as being necessary for the defense of the Catholic faith and/or the liberty of the Church.
Reflecting the very different “political” conditions encountered in these distinct contexts, each of these types of religious war developed its own distinctive character. But each was also powerfully conditioned – indeed, made possible – by a common institutional and legal framework (the idea of the “crusade” as codified in canon law and theology), a common politico-military infrastructure (the crusader army, the military religious orders), and a common moral purpose (the defence of the Church and Christendom, the redress of injustice). Put slightly differently, each was a manifestation of a common historical structure of war. In this chapter, I trace the contours of the specific types of violent religious conflict always immanent within the historical structure of medieval war.
The crusades, on this account, were artifacts of neither the timeless logic of anarchy nor the feudal mode of production/exploitation. Nor were they simply the geopolitical derivatives of socially constructed religious mentalités collectives. Nor, significantly, were they a function of the logic of the late medieval state-system. Rather, they were organic expressions of the historical structure of medieval religious war. This structure comprised three elements. The first of these was the development of a distinctive war-making capability on the part of the post-Gregorian Church. The second was the crystallization of a socially constructed identity-interest complex that placed this Church in a structurally antagonistic relationship with a range of other social forces both within and beyond Latin Christendom. And the third was the evolution of the social institution of “crusade” – an institution that both legitimized war as an instrument of ecclesiastical statecraft and re-constructed the armed nobility that provided the core of Latin Christendom’s war-fighting capacity as “soldiers of Christ” willing and able to fight on behalf of the Church and its interests. This historical structure did not “cause” the crusades – at least not directly. Rather, it established the essential conditions-of-possibility for each of the specific crusades that took place during the later medieval era. Once it had crystallized, ecclesiastical war became an always-immanent feature of the geopolitical relations of Latin Christendom; once it had passed from the historical scene, crusading – while formally persisting for centuries – became little more than a vestigial remnant of a bygone era, increasingly out of place in the post-medieval world order of Early Modern Europe.
The Crusades to the Holy Land
As Riley-Smith has argued, following the “birth” of the crusading movement and the First Crusade, the history of the crusades to the Holy Land can be organized into several discrete phases. The first of these, c. 1102-87, he describes as that of “crusading in adolescence”. During this phase, the Church and crusader principalities were forced decisively on to the defensive by an increasingly unified Islamic polity committed to the reconquest of Jerusalem and the extirpation of the Christian presence in Syria and Palestine. The success of the First Crusade was largely a function of disunity and internecine conflict in the Islamic world. This was also true of the period in which the Crusader States were established – disunity among the contiguous Muslim polities (Rum, Aleppo and Mosul, Damascus, Egypt, Seijar, Hama, Homs) meant that the Christian princes could play them off against one another to great strategic effect. Almost immediately after the liberation of Jerusalem, however, Muslim opposition began to coalesce: Egyptian forces, for example, attempted to retake Jerusalem as early as 1099, as did those of the sultanate of Iraq beginning in 1110. Ominously from the Church’s perspective, an increasingly unified Muslim state centered on Mosul and Aleppo began to coalesce in the 1120s. When a new governor, ‘Imad as-Din Zengi, was appointed in 1128, he led this newly unified emirate on a series of campaigns intended to further extend what had become his personal domain at the expense of both his Christian and Muslim neighbours. When in 1144 the count of Edessa entered into a defensive alliance with one of Zengi’s Muslim adversaries, Zengi sensed an opportunity and attacked the county. Edessa, the capital of the first crusader principality and a cornerstone of the strategic defenses of Jerusalem, fell to Zengi’s forces on Christmas 1144.
Almost as soon as they had taken Jerusalem in 1099, the crusader leadership realized that if the Holy Land were to be made secure it would be necessary to create a kind of defensive buffer around Jerusalem. In addition to an “inner ring” formed by the principalities founded during the First Crusade, this would also require an “outer ring” comprising the key strategic towns of Ascalon, Aleppo, Damascus and the Mediterranean ports, all of which could provide staging areas for any future Muslim counteroffensive against the Kingdom of Jerusalem. With the fall of Edessa, this strategy was seriously compromised. On 1 December 1145 Pope Eugenius III reacted to this unwelcome development by issuing a general letter entitled Quantum praedecessores, which called for a second crusade to fight in defence of the Holy Land. Following a poor initial response, the encyclical was reissued on 1 March 1146 and Abbot Bernard of Clairvaux was charged with preaching the crusade in France and Germany. Quantum praedecessores was augmented by a second encyclical issued in October of that year – Divini dispensatione – addressed specifically to the Italian clergy. In addition to calling on the armed laity to take the cross and come to the aid of their besieged brethren in Outremer, both of these letters offered those who took the cross remission of sins, protection of property and other privileges. The former also outlined the motives behind this call to crusade: on the one hand, the need to right the injustices perpetrated by the Muslims (the unlawful seizure of one of the oldest of all Christian cities; the spoliation of the local Church and its relics; and the murder of the local archbishop and his clergy); and, on the other, the need to deal with the threat to the Church and all Christendom posed by the loss of the city. The latter extended the crusade to Iberia and the Baltic frontier, in effect authorizing a three-front campaign to defend and expand Latin Christendom.
The response to the call was an extraordinary mobilization of the armed laity of the Latin world. In 1147, two massive armies – one under the leadership of King Louis VII of France; the other under Conrad III of Germany – embarked in quick succession on the overland route through Byzantine Greece and Anatolia to Syria. Despite the tremendous enthusiasm generated by the venture, however, the sad reality (from the Church’s perspective) was that these crusader armies were simply not up to the task of taking on the Muslims threatening Outremer. Against the backdrop of political maneuvering amongst the French, German and Byzantine leaders, the Seljuk Turks inflicted crushing defeats on Conrad’s army at Dorylaeum and Louis’ army at Laodicea, both in Asia Minor. Despite the clear danger posed by the unification of Egypt and Syria under Saladin in 1174, the resulting demoralization and disillusionment mooted the possibility of a major crusade to the East for the better part of a generation. 
The second phase in the history of the crusades to the Holy Land, that of their “coming of age”, began with the fall of Jerusalem to Saladin in 1187 and ended with its restoration to Latin Christendom in 1229. Above all else, this phase was characterized by a profound change in geopolitical purpose: during this period, the crusades were no longer prosecuted in defence of Jerusalem, but for its recovery. After the failure of the Second Crusade, the jihad against the Christian principalities provided both a common goal and a unifying religious focal point for the Muslim polities in the region. Building on this, Zengi’s son and successor, Nur al-Din, first created a unified Syrian emirate and then entered into an alliance with Egypt for the purpose of putting pressure on the Christians. On his death, the vizier of Egypt, Saladin, invaded Syria, creating for the first time a truly unified Muslim polity surrounding Outremer. Once he had consolidated his hold over this “empire”, Saladin resumed the jihad against the crusader principalities. After a somewhat chequered period marked by a few notable victories and several serious defeats, and at a point when “the Christians were exceptionally weak and divided”, Saladin’s army attacked Tiberias. When the Christian army marched to relieve the besieged citadel, Saladin caught them in a highly unfavourable position and inflicted a devastating defeat upon them at the Battle of Hattin. The majority of the massive Christian host was killed or captured, including the King of Jerusalem, the Master of the Temple and many other important leaders. The True Cross, recovered during the First Crusade and typically carried into battle by the King of Jerusalem, was captured and paraded upside down through the streets of Damascus by the victorious Muslims. With the principalities denuded of their best fighting men, Jerusalem fell to Saladin’s forces on October 2,1187. By the time Saladin was finished his campaign, Outremer had been reduced to little more than the coastal enclaves of Tripoli, Antioch and Tyre.
On October 29, 1187 Pope Gregory VIII responded to these catastrophic developments by issuing an encyclical – Audita tremendi – that called upon the princes, nobles and knights of Latin Christendom to launch an expedition to liberate Jerusalem once again from the Muslims. The encyclical began by characterizing the disastrous fall of Jerusalem as punishment for the collective sinfulness of all Christendom; the city had been lost, so the pope argued, because of the sins of Christians everywhere. This being the case, the encyclical continued, the redemption and liberation of the Holy Sites necessarily required penitential sacrifice by Christians everywhere. In effect, the pope called on Latin Christendom to redeem itself through acts of contrition, piety and purification, including participation in an expedition to liberate Jerusalem. In practical terms, the encyclical also sought to facilitate such an expedition by imposing a seven-year truce throughout Latin Christendom and by mobilizing the princes and nobles of Latin Christendom by offering them the now-usual indulgences, privileges and protections in exchange for their penitent participation in an armed pilgrimage to Jerusalem.
The response to Gregory’s call was “the largest military enterprise in the middle ages”. Richard I (Lionheart) of England, Phillip II (Augustus) of France and Frederick I (Barbarossa) of the Holy Roman Empire all led vast armies to the Holy Land. Once again, however, the campaign was to prove ill-fated. Frederick drowned en route, leaving only a rump force under the command of Duke Leopold IV of Austria to press on to Palestine. Divisions among the three temporal crusade leaders subsequently led to the departure of Leopold and Phillip from the Holy Land in 1191. This left only Richard to continue the campaign, which he did ably and with some notable military successes against Saladin. When he began his campaign, the Latin kingdom comprised little more than a handful of coastal cities and a few isolated inland fortresses; when he was finished, it consisted of the whole coast from Tyre to Jaffa. However, while Richard had effectively reversed most of Saladin’s gains since the Battle of Hattin, he was able neither to break the sultan’s army nor force him to abandon Jerusalem. The best he could manage was a negotiated settlement that guaranteed unarmed Christian pilgrims access to the holy sites, but that left the Holy City in Muslim hands. Having achieved this – and created the geopolitical conditions necessary for the Kingdom of Jerusalem to survive for another century – Richard quit the Holy Land for good in 1192.
While Richard’s campaign against Saladin was in some ways remarkably successful, from the Church’s perspective it manifestly failed to achieve the goals articulated in Audita tremendi. To be certain, the crusader principalities had been restored and their strategic position greatly enhanced. But, as Madden puts it, “the purpose of these states was the protection of the holy sites; they were not an end in themselves”. To the papacy and many of Latin Christendom’s temporal leaders, Richard’s inability to liberate Jerusalem from Saladin’s grip was a crushing setback – one that needed to be reversed at the earliest possible opportunity. The failure to realize this crucial objective thus set the stage for three more major crusades, all intended to restore the holy sites to Latin Christendom. In 1198, Pope Innocent III (1198-1216) issued the encyclical Post miserable, launching the Fourth Crusade (1202-1204). The avowed objective of this campaign was “the liberation of Jerusalem by an attack on Egypt”. It was, however, soon diverted into an attack on the Byzantine capital, largely as a result of the strategic calculation that “a Constantinople in reliable western hands might be deemed as much of an asset for the liberation of Jerusalem as the conquest of Alexandria”. While it succeeded in establishing the Latin Kingdom of Constantinople, this crusade too manifestly failed to realize its declared goal of liberating Jerusalem. The Fifth Crusade (1217-1221), also launched by Innocent, was similarly intended to harness the “full economic, military and spiritual might” of Latin Christendom to the task of liberating Jerusalem, this time under even tighter Church leadership. The proximate objective of the crusade was again Egypt – the Nile port of Damietta was to be captured and used as a base for an attack on Cairo which was in turn to be used as a base for the liberation of Jerusalem. Following extensive preparations, Damietta was attacked and captured in 1219. In August 1221, however, the crusader army found itself surrounded by Muslim forces near El Mansura and was forced to withdraw from Egypt. For all its efforts, this crusade achieved little more than an eight-year truce and a (never fulfilled) promise that the relic of the True Cross – lost to Christendom at the Battle of Hattin in 1187 – would be returned. The Sixth Crusade (1228-1229) was to prove considerably more successful, though more due to skilful diplomacy than marital prowess. Under pressure first from Pope Honorius III and later from Gregory IX, the Holy Roman Emperor and King of Jerusalem, Frederick II, finally embarked on his long-promised crusade in 1228. He launched his expedition, however, without papal approval because, having failed for so long to fulfill his crusader vow, he was under sanction of excommunication. While his status as an excommunicate caused him considerable political difficulty – he was not afforded crusader protections and privileges; he was opposed by the military orders – Frederick was nevertheless able to force the sultan of Egypt, al-Kamil, to the bargaining table. Against the backdrop of al-Kamil’s efforts to consolidate control over his own newly acquired Syrian territories, Frederick was then able to pressure him into signing a treaty that effectively surrendered Jerusalem to the Christians. While the treaty itself no longer survives, its terms were widely reported in contemporary accounts. On the one hand, in return for a much-needed ten-year truce, al-Kamil agreed that the Kingdom of Jerusalem would extend from Beirut to Jaffa and would include Bethlehem, Nazareth, Belfort and Montfort and the city of Jerusalem (which would be demilitarized). On the other, Frederick agreed that the Muslim inhabitants would retain control over their holy sites (the Dome of the Rock and the Temple of Solomon), remain in possession of their property, and administer their own system of justice. He also agreed that the Kingdom of Jerusalem would stay neutral in any future conflict between the sultanate and the Christian principalities of Tripoli and Antioch. While condemned by many at the time for the “humiliating” nature of its outcome, in geopolitical terms the crusade was clearly a success: the city of Jerusalem was restored to Latin Christendom and the Kingdom of Jerusalem rebuilt as its defensive glacis.
The third phase of crusading in the Holy Land – that of its “maturity” – began with the expiration of Frederick’s truce in 1239 and ended with the fall of the last remnant of Outremer, the city of Acre, in 1291. Its opening act involved the occupation of the defenceless city of Jerusalem by the forces of the Muslim emir of Kerak in 1239. Against the backdrop of internecine conflict in the Muslim world, over the next two years minor crusader armies were able to play Muslim factions of against each other, thereby securing the return of the city of Jerusalem and greatly extending the frontiers of the Kingdom of Jerusalem. But the regional balance of forces soon shifted again and the Muslims retook the defenceless city in 1244, subsequently massacring its Christian inhabitants and torching the Church of the Holy Sepulchre. This set the stage for the final three acts of this phase of the crusades to the East. The Seventh Crusade (1248-54), led by King Louis IX of France, was a direct response to the loss of the Holy City. Louis led a massive army to Egypt, occupying Damietta almost without resistance and then advancing on Cairo. Stiffening Muslim resistance and an outbreak of dysentery within the crusader army, however, turned the tide and Louis was forced to withdraw toward his operational base at Damietta. Additional Muslim successes soon rendered the crusader army’s position untenable and Louis’ first bid to liberate Jerusalem ended with him surrendering to the sultan of Egypt on April 6, 1250. The Eighth Crusade (1270) was King Louis’ second attempt to liberate the holy sites. This time he adopted a three-step strategy: first, attack Tunis; second, advance along the north African coast and take Egypt; and, third, liberate Jerusalem. At first, the expedition went well: Carthage fell to Louis in July 1270 and a Sicilian fleet led by Charles of Anjou was nearing the port with reinforcements that would allow the king to exploit this initial victory. On August 25, however, Louis died of dysentery; the crusade was abandoned shortly thereafter. Finally, in the immediate aftermath of the failed Eighth Crusade, Prince Edward of England led an expedition to the Holy Land to help defend Tripoli and the rump Kingdom of Jerusalem. This was the Ninth Crusade (1271-2), conventionally considered to be the last major crusade to the Holy Land. It ended when a treaty was signed between Egypt and the Kingdom of Jerusalem. Upon the death of his father, King Henry III, Edward returned home to assume the English throne.
As this necessarily schematic sketch clearly indicates, the crusades to the Holy Land were a powerful expression of the historical structure of war of later medieval Latin Christendom: they reflected the distinctive war-making capacity of the Church (the crusader army and the military religious orders); they expressed the socially constructed interests of the reform papacy (the liberation and defence of Jerusalem); and they were made possible by the institution of the crusade (constituting the Church as a legitimate war-making unit and the “crusader” as a recognizable form of actor with a defined portfolio of religious interests). Of course, crusading was not the only form of war conducted by Christian powers in the Holy Land. The dynamics of public war were clearly at work throughout the two-centuries long Latin political presence in Syria and Palestine. Nevertheless, any serious account of medieval geopolitics must recognize and take into account the distinctiveness of these ecclesiastical wars. While often intertwined with other forms of violent conflict, the crusades were not reducible to them; nor were they motivated by the same underlying constellation of war-making units, structural antagonisms and institutions that gave rise to these other forms of war. Rather, they were a distinctive form of organized violence – one that would quickly find expression in other parts of Latin Christendom.
The Iberian Crusades
The pre-history of the Iberian Crusades can be traced to the disintegration of Umayyad Caliphate of Córdoba in 1031 and the subsequent emergence of a constellation of weak successor kingdoms – Badajoz, Seville, Grenada, Málaga, Toledo, Valencia, Denia, the Balearic Islands, Zaragosa and Lérida – known as taifas. Locked in intense internecine competition, these emirates soon began to seek the “protection” of the militarily stronger Christian kingdoms of León, Castille, Navarre, Aragón and Catalonia. In turn, these Christian kingdoms began to vie with one another for the tributary payments (parias) paid by the taifas for protection. In this complex regional system, the geopolitical fault-lines were not always drawn along religious or civilizational lines: as O’Callaghan puts it, “[j]ust as Muslim kings concluded that it was prudent to become vassals of their Christian neighbors, paying tribute and joining in attacks on their fellow Muslims, so too, when it suited their purpose, Christian princes did not hesitate to make alliances with Muslims”. Nor were they stable: alliances and tributary arrangements changed as perceptions of advantage or insecurity shifted. And while territorial expansion at the expense of the taifas was certainly part of the dynamic of this system (witness Fernando I’s conquest of the town of Coimbra from the taifa of Badajoz in 1064), it was not its defining characteristic. Rather, the dominant logic of Iberian geopolitics during this period was maneuvering for advantage among the taifa statelets coupled with competition over the parias (which had both proprietorial and state-building dimensions) among the now-dominant Christian principalities.
It was against this backdrop that in 1063 Pope Alexander II encouraged Christian knights from within and beyond Iberia to wage war on the taifas. Reflecting his worldview as one of the early reform popes, Alexander was greatly concerned by the general military threat posed to Christendom by Islam. Indeed, in common with Gregory VII and Urban II, Alexander “considered the military threat posed to Christianity by Islam, and its eschatological context, at least as much in terms of the struggle in Iberia as in that of wars occurring in the Middle East”. Sensing an opportunity to liberate at least some of the once-Christian lands of the peninsula from Muslim rule, Alexander responded to an appeal for assistance from the Christian king of Aragón by issuing a bull – Clero Vultutnensi – that offered relief from penance and remission of sin to any and all Christian warriors participating in his planned expedition against the taifa of Zaragosa. In response, a large number of knights from Burgundy, Normandy, Aquitaine, Italy, and all over Christian Iberia journeyed to Aragón to take part in the campaign. The fort at Barbastro – a strategically important site about sixty miles north of the town of Zaragosa – was subsequently taken this army and held until recaptured by Muslim forces in late 1065.
Following several lesser actions in which Pope Gregory VII may have offered similar religious inducements to fight, in 1089 another major proto-crusade was launched by Pope Urban II. The geopolitical context within which this campaign was undertaken was quite different from that prevailing in the 1060s. In 1085, King Alfonso VI of Castile captured Toledo, convincing the emirs of the taifa statelets that they faced an increasingly lethal threat to their existence. They subsequently appealed to the Almoravids – a puritanical Sunni sect that had recently subjugated Morocco – to help them resist the Christian campaign of reconquest. Responding to this appeal, but also acting on their belief that the taifas were decadent and in need of their particular brand of religious reinvigoration, the Almoravids crossed the Straits of Gibraltar and entered Iberia in force. In 1087, they routed King Alfonso’s army at the battle of Sagrajas near Badajoz, thereby stemming the Christian advance, ending the parias system and so simultaneously dealing a severe geopolitical and economic blow to the Christian principalities. Over the next two decades or so, the Almoravids then proceeded to incorporate the remaining taifas into their empire. These developments gravely concerned Church officials, who saw in them not only a reversal of the re-conquest, but a growing threat to Christian Spain, southern France and, ultimately, all of Christendom. In a bid to “create a wall and bastion against the Saracens”, the pope offered remission of sins to those Catalan nobles who undertook to liberate and restore a number of important metropolitan sees under Muslim control (Braga, Mérida, Seville and Tarragona). While not yielding immediate successes, the call nevertheless resulted in the mobilization of considerable number of knights committed to the goal of liberating Tarragona. In some ways anticipating the future evolution of the Military Orders (Templars, Hospitallers, Teutonic Knights, etc.), it even led to the creation of novel form of “military confraternity” – comprising knights living communally in frontier fortresses – dedicated to liberating and restoring the See in return for the remission of their sins.
These early campaigns, clear expressions of the historical structure of medieval war as it had begun to crystallize in the 11th century, are significant for two reasons. First, they contributed to the evolution of the crusade proper as a defining element of the geopolitical system of medieval Latin Christendom. During these campaigns, many of the elements that were later to coalesce into the institution of the crusade were first developed: the use of papal bulls to mobilize the armed laity, the remission of sins in return for service, the invocation of the Peace of God in order to secure the internal tranquility necessary for campaigning against the Muslims, and the trans-local nature of the forces responding to the call all anticipated the character of crusading proper. While there is no denying that some of the institution’s defining elements – such as the vow and the sense of pilgrimage – were not present in these pre-1095 campaigns, there is also no denying that these experiments laid the institutional groundwork for the First Crusade to the Holy Land. Second, these campaigns initiated a process of transformation that radically altered the overall character of the Reconquista. Space limitations preclude a detailed account of this broader process. Suffice it to say, however, that whereas prior to the 1060s the re-conquest was driven by the inter-twined logics of lordly political accumulation and princely state-building, after the Barbastro campaign it was increasingly driven by the logic of religious defense and expansion (defensio and dilatio) as well. To be sure, the more mundane dynamics of the Reconquista never disappeared: it was always in some substantial measure about the configuration, wealth and power of the peninsula’s Christian kingdoms and lesser principalities. After 1063, however, a significant new religious dimension was introduced that profoundly transformed the causes, character and correlates of war in the region. If not completely reconfiguring the Reconquista into a sort of perpetual crusade – as O’Callaghan seems to argue – this development clearly reshaped the basic patterns of violent political conflict in the peninsula for centuries to come.
The next phase of Iberian crusading – running from 1095-1123 – was a period of bricolage and experimentation during which the constitutive ideal of the crusade – forged decisively during the successful expedition to Jerusalem in 1099 – was purposefully introduced to Iberia. As with the experiments before 1095, the impulse to introduce crusading proper to the peninsula was provided primarily by developments in the Islamic world – specifically, by the continuing successes of the Almoravids in both weakening the Christian kingdoms and consolidating their own. By 1110, this process was completed with the incorporation of the last remaining taifa – Zaragosa – into their empire. With internal consolidation complete, the Almoravids were free to intensify their pressure on the Christian kingdoms of Léon-Castile and Aragón , prompting the rulers of these kingdoms in turn to appeal to the papacy for assistance.
The reform popes of the period – Urban II, Paschal II, Gelasius II, Calixtus II – viewing the threat in Iberia in its broader eschatological context, responded to this appeal by mobilizing the only military instrument then available to them: the crusader army. Drawing on the constitutive ideal of the successful 1095 expedition to Jerusalem, the papacy almost immediately began to introduce the formal apparatus of crusading – bull, preaching, vow, indulgence, privilege, signing with the cross – to the Iberian region in order to mobilize the martial resources of Christendom against the Almoravids. This resulted in two crusades between 1113-8. The first of these, authorized by Pope Paschal in 1113, was a joint Pisan-French-Catalan expedition to liberate Christian captives being held in the Balearic Islands; the second, proclaimed in 1118 and led by King Alfonso I of Aragón-Navarre, was a campaign to capture Zaragosa. While there is some debate as to whether they were full-fledged crusades or merely a type of Iberian proto-crusade, these two campaigns clearly reflected the Church’s new-found desire not merely to sanctify and encourage the Reconquista, but to use its recently acquired and distinctive war-making capacity to advance its own socially constructed interests in the region.
The final stage, from 1123 onwards, was that of Iberian crusading in maturity. As argued above, crusading in Iberia prior to 1123 involved either innovations that anticipated the First Crusade of 1095 or, after 1099, piecemeal applications of crusading practices that had crystallized as a result of that campaign. In 1123, however, the First Lateran Council decisively ruled that the Iberian crusades were of a piece with those to the Holy Land. From this point on, the crusades in Iberia were seen as part of a wider conflict against Islam – usually as a kind of “second front”, though sometimes as an alternate route to the East and steps were often taken to coordinate (or at least “de-conflict”) crusades in the two theaters. As importantly, with the full application of the increasingly well-defined crusade institution in Iberia, crusader armies could be more readily mobilized by the Church to advance its interests in the peninsula. Taking advantage of this new capacity, the papacy authorized a number of Iberian campaigns – one conducted by Alfonso VII of Castile against Almería on the southern coast of Granada 1147; another, conducted by a joint Catalan-Genoese force, against Tortosa at the mouth of the Ebro in 1148 – in support of the Second Crusade (1145-9). Popes Eugenius III and Anastasius IV also authorized a crusade by Count Ramon Berenguer IV to consolidate control of the Ebro valley between 1152 and 1154, and one by King Alfonso VII to capture Andújar in 1155. 
From the mid-1100s onward, however, the Church was increasingly concerned with the threat to Christendom posed by the Almohads, a fundamentalist Islamic sect originating in Morocco that had begun displacing the Almoravids as rulers of Muslim Iberia. Against the backdrop of continuing rivalry among the Christian principalities, for several decades this new empire reversed the geopolitical dynamic in the peninsula, winning several important battles, and retaking territory that had been lost in the later years of the Almoravid regime. In 1172, the Almohads seized the last Almoravid emirate in Iberia. The period of Almohad expansion was not to last for long, however. Faced with the grave threat to Christian Iberia posed by the resurgent Muslim forces, the Christian princes (with papal encouragement) began to employ a number of religious military orders as a bulwark against further Almohad advances. As Houlsey observes, this phenomenon had both a local and translocal dimension. On the one hand, each of the Christian kingdoms (except Navarre) created its own orders. These included the larger and more long-lived orders such as Alcántara, Calatrava, and Santiago, as well as more ephemeral ones such as Le Merced, Monte Gaudio, San Jorge de Alfama, and Trujillo. On the other hand, the Templars and the Hospitallers, both iconic translocal orders, had a significant presence in the peninsula, especially in Aragón and Catalonia. Taken together, these orders provided a permanent defensive carapace along the frontier – a carapace that contributed substantially to the frustration of the Almohad advance in the latter part of the 12th century.
Not content with merely stabilizing the frontier in Iberia, during this period successive popes offered remission of sins and other spiritual inducements to those fighting to drive the Muslims out of Iberia. In 1175, Pope Alexander III used the promise of the same indulgence given to crusaders to the Holy Land to encourage Christian rulers of Léon, Castile and Aragón to go on the offensive against the Almohads. In an effort to prevent any large-scale departure of penitential warriors from Spain to the Holy Land following the proclamation of the Third Crusade (to liberate Jerusalem, which fallen in 1187), Pope Clement III extended the scope of that crusade to include Iberia. In response, Alfonso VIII went on the offensive south of the Guadiana River and, more importantly, non-Iberian crusaders on their way to the Holy Land engaged in a joint venture with Sancho I of Portugal to capture the town of Silves (the Crusade of Silves, 1189). Also encouraged by the extension of the Crusade bull to Iberia, Alfonso VIII embarked upon the ill-fated Crusade of Alarcos (1193). Against the backdrop of successful and crucial papal efforts to end the internecine struggles among the peninsula’s Christian princes, the Crusade of Las Navas de Tolosa was launched in 1212. Culminating in a decisive Christian victory, the campaign effectively broke the back of the Almohad empire and constituted a tipping point of sorts in the long conflict in Iberia. The preceding century or so had been one of geopolitical stalemate, with the frontier whip-sawing back and forth according the always-shifting balance of forces between the Muslim and Christian powers. After Las Navas, however, the Almohads never again managed to recover their footing, and their empire entered into a period of terminal decline. Four decades (and several crusades) later, al-Andalus had been all but extinguished and almost all of Iberia had been permanently reincorporated into the Latin Christian world order.
Perhaps not surprisingly, over the course of several centuries the Iberian Crusades developed their own distinctive character: “pilgrimage” was far less important than in the crusades to the Holy Land; they were closely controlled by Iberian monarchies (especially Léon-Castile); they were more successful than those in the East (especially after the Battle of Las Navas in 1212); they were more reliant on both regional and trans-regional military orders; and the Iberian “crusader states” – unlike those in the Holy Land – developed strong fiscal and administrative bases from which to launch both political wars and crusades. But they were nevertheless also clear expressions of an historical structure of war that transcended the Iberian sub-system: they reflected the distinctive war-making capacity of the Church (the crusader army and the military religious orders); they expressed the socially constructed interests of the reform papacy (the restoration of once-Christian lands in Spain to the Latin Christian fold); and they were made possible by the institution of the crusade (constituting the Church as a legitimate war-making unit and the “crusader” as a recognizable form of agent with a defined portfolio of religious interests). Of course, this does not explain the totality of the historical process known as the Reconquista. It does, however, highlight the distinctively ecclesiastical or religious dimension of the process – a dimension that was organic to the historical structure of war in later medieval Latin Christendom.
The Northern Crusades
As Peter Lock has characterized them, the Northern Crusades were conducted in five partly overlapping phases: the Wendish Crusades (1147-85), the Livonian and Estonian Crusades (1198-1290), the Prussian Crusades (1230-83), the Lithuanian Crusades (1280-1435), and the Novgorod Crusades (1243-15th century). While authorized by, and fought on behalf of, the Church these wars were prosecuted by Danish, Saxon, and Swedish princes as well as by military orders such as the Sword Brothers and the Teutonic Knights. They were fought primarily against a range of pagan adversaries – Wends, Livonians, Estonians, Lithuanians, Suomi, and Prussians – although some were also waged against Russian Christian schismatics (i.e. adherents to the Greek Orthodox rite). By the early 16th century, these ecclesiastical wars – always only one element of broader process of the expansion of medieval Europe – had contributed significantly to extension of the northeastern frontier of Latin Christendom and the transformation of the Baltic from a pagan mare incognita into a Latin Christian lake.
The pre-history of the Northern Crusades can be traced to the so-called Magdeburg Charter of 1107/8 – a document that explicitly called for an expedition to be undertaken against the Baltic pagans. Although there are a number of debates about the provenance and purpose of this document, it is important for the purposes of this study in that it constitutes the earliest known text in which the crusading idea is grafted on to pre-existing ideas about the dangers and opportunities confronting the Church on the northeastern frontier of Latin Christendom – i.e. the earliest translation of the idea of the crusade to the Baltic region. Several themes running through the document are particularly significant. To begin with, it depicts the pagan Slavs in terms redolent of depictions of Muslims in accounts of the First Crusade – i.e. as “oppressors” guilty of committing grievous “injuries” against the Church and its members. Second, it portrays the pagan lands as “our Jerusalem”, a land of milk and honey lost to the heathen because of sinfulness of the Christians in the region. Third, it calls on the “soldiers of Christ” to liberate this Jerusalem, implying that doing so will create conditions favourable not only for settlement but for evangelization as well. While the charter’s call to arms came to nothing at the time, it expressed ideas that were circulating widely among the clerics in the region and that over time would come to exercise an increasingly powerful grip on the collective imagination of the highest levels of ecclesiastical leadership.
The formal introduction of the crusade to northern Europe can be attributed to Pope Eugenius III’s 1147 encyclical Divini dispensatione, which extended the scope of the Second Crusade to include not just the Holy Land, but Iberia and the Wendish (West Slavic) lands adjoining Saxony as well. The explicit objectives of the expedition were to subject the pagans to the Christian faith – a goal that came close to contradicting canon law prohibiting forced conversions. Reflecting many of the themes of the Magdeburg Charter, however, senior Church officials – including, significantly, Pope Eugenius and Bernard of Clairvaux, the chief ideologist of the Second Crusade – almost certainly regarded this expedition as a just war fought primarily to defend Christian missionaries and converts from harassment at the hands of the pagan Wends and to create a political context conducive to the peaceful expansion of Christendom through missionary work. As Hans-Deitrich Kahl has argued, these core eschatological motives were also at least inflected by a powerful belief that the second coming of Christ was imminent (with all that this implied for the prospect of mass conversion). Proceeding hand-in-hand with territorial expansion on the part of the Saxons, the region had seen extensive missionary activity in the preceding decades. Not surprisingly, the Wends had resisted both of these activities, on the one hand mounting military campaigns against the Saxons, on the other destroying missions, martyring missionaries and menacing local converts into apostasy. When the crusade encyclical Quantum praedecessores was proclaimed following the fall of Edessa in 1144, the state of affairs on the Wendish frontier was such that the Saxon nobility responded only half-heartedly to the Church’s call, asking instead to be allowed to campaign against the pagan Wends with whom they were already embroiled in conflict. This was supported by local clergy, who argued that Christians converts – and thus the future of evangelization in the region – could only be made secure if the Wends were brought under Christian rule. Given the centrality of evangelization to the core ontological narrative of the Church – as well, perhaps, as the general enthusiasm generated by the proclamation of the Second Crusade – Eugenius not surprisingly responded positively to this request. He subsequently appointed Bishop Anselm of Havelburg as papal legate, authorized an expedition to subject the Wends to Saxon lordship (thereby creating the conditions within which the permanent evangelization of their territory could take place), and promised those crusading in the North the same indulgence (and many of the same privileges) as had been granted by Urban II to those fighting in the First Crusade.
Responding to the papal proclamation, in 1147 a crusader army comprising Saxon, Polish and Danish contingents invaded the Wendish lands. While this army enjoyed some successes on the battlefield, however, it ultimately failed in to achieve its primary goal: the destruction of paganism in the Wends’ territories and their decisive incorporation into Latin Christendom. As Iben Fonnesberg-Schmidt has shown, this prompted the Church to reconsider the whole enterprise of crusading in the Baltic. For several decades after 1147, the papacy demonstrated a considerable lack of enthusiasm for any further crusading in the North and neither local ecclesiastical nor lay authorities petitioned for one. Wars continued to be fought in the region in the aftermath of the Wendish crusade, of course, but “they were fought without benefit of papal authorization, or any of the apparatus of the crusade; there was no vow, no ad hoc legatine commission, no special preaching or promises of crusade privileges”. Indeed, it was not until 1171 that Pope Alexander III (1159-81) issued a new crusading bull for the region (Non parum animus noster), and even then he recast these expeditions as “penitential wars” – similar to crusades to the Holy Land, but offering fewer spiritual rewards, privileges and protections and enjoying a somewhat lower status. The wars against the Wends continued, however, led by men such as Duke Henry the Lion of Saxony (1142-95) and King Valdemar the Great of Denmark (1157-82). As Christiansen puts it, these campaigns were “wars carried on successfully in the shadow of the unsuccessful 1147 crusade”. After decades of brutal conflict, by 1185 the Wends had been effectively pacified, their pagan regime destroyed, and political and ecclesiastical structures more conducive to Christianization erected in their place.
When Alexander issued his bull of 1171 he not only re-introduced the institution of the crusade – or at least a diluted version of it in the form of “penitential war” – to Northern Christendom; in a marked departure from past practice, he also outlined a papal vision for the evangelization of the entire East Baltic region. This vision had two key elements. First, it entailed a commitment to the armed defence of the Christian Church and its missions in the region. Alexander had received troubling reports that the mission in Estonia was subject to repeated pagan attacks – attacks that he viewed as both unjust (contrary to the ius gentium) and a serious threat to the Church’s core mission of evangelization. Accordingly, he authorized the use of armed force in the defence of the Estonian mission and granted limited indulgences to those fighting in this just cause. Second, Alexander envisioned a significant expansion of the northern frontiers of Latin Christendom to include, at a minimum, Estonia and Livonia. This latter part of the vision, Alexander argued, was to be accomplished through peaceful missionary work if at all possible, but through the use of armed force if necessary. By combining the goals of both defensio and dilatio, Alexander’s 1171 bull established the basic approach to crusading in the North: in Erdmann’s terms, “indirect missionary war”. In the future, peaceful missions would be established in pagan territory; when these incurred local hostility, they and their activities would be defended by penitential warriors; and finally, when circumstances seemed propitious, the pagan “problem” in that particular region would be resolved by forcibly incorporating the catchment area of the endangered mission into Latin Christendom through crusade.
The mission of Bishop Meinhard to the pagan Livonians powerfully illustrates this expansionary dynamic. With the support of both the Archbishop of the missionary see of Hamburg-Bremen and the papacy, Meinhard established a mission in the Dvina River basin around 1180. Sensing an opportunity for large-scale conversion, Meinhard offered the Livonians a bargain: in return for their agreement to undergo baptism he would build two fortifications on islands in Dvina River (Üxküll and Holm) to protect them from their enemies among the other pagan peoples of the region. According to the chronicler Henry of Livonia, the Livonians freely accepted this offer. When they realized that all those who converted were also going to be held financially responsible for the upkeep of these fortifications, however, the Livonians balked: few among them actually accepted baptism or placed themselves under the authority of the bishop. Viewed from Meinhard’s perspective, this constituted a grave breach of the Livonians’ promise to convert. It also presented him with a serious problem. Not only was he not attracting many converts, but those few Livonians whom he did baptise (the only people Meinhard actually had any authority over) simply did not constitute a tax-base capable of supporting the mission’s castles and their garrisons. Meinhard realized that if he could not maintain these forces he would not be able to provide the protection he had promised, fatally undermining his entire strategy for evangelizing the region. The Bishop’s problem was compounded by the fact that the relatively high taxes he was forced to levy on his small flock of converts actually provided a strong financial incentive to apostasy – he was losing souls faster than he was gaining them. Meinhard’s solution: expand the tax base by compelling the Livonian people to keep what he believed to be their promise to convert. When persuasion and threats failed to compel the Livonians to come in, the bishop appealed to Rome for the military forces needed to implement this strategy.
Gravely concerned by the Livonians’ apostasy and their collective failure to honour the terms of their agreement with Meinhard, in 1195 Pope Celestine III responded positively to the Bishop’s appeal, granting limited remission of sins to those agreeing to take the cross to fight in Livonia. An expedition was subsequently launched under the leadership of the Duke of Sweden, but failed to achieve much before Duke returned home with the majority of the crusader army. Following Meinhard’s death in 1196, his successor – the Cistercian Bishop Berthold – led another expedition against the Livonians, explicitly justifying the campaign in terms of restoring the apostates to the faith. When Berthold was killed in 1198, Pope Innocent III authorized yet another Livonian crusade, this one led by the newly elected Bishop Albert of Buxhövden. This and subsequent crusades – all explicitly justified in terms of defending the Church from pagan harassment, restoring apostates to the faith, and/or creating conditions propitious for evangelization – were far more successful, ultimately resulting in the destruction of the Livonians’ war-making capacity and with it their ability to resist incorporation into Latin Christendom. By the time of Albert’s death in 1229, Livonia been made an imperial fief and most Livonians had been converted to Latin Christianity.
Thus ended the early phase of Northern crusading. The crusades that took place during the subsequent high phase – specifically, the Prussian Crusades (1230-83), the Lithuanian Crusades (1280-1435), and the Novgorod Crusades (1243-16th century) – all shared the same basic structural character as the indirect missionary wars against the Livonians, but were differentiated from them in significant ways. First, from the earliest decades of the 13th century on, the Baltic wars were distinguished from earlier expeditions by their elevation from “penitential wars” to full-blown “crusades”. As Fonnesberg-Schmidt has convincingly demonstrated, crusading in the Baltic prior to 1230 involved piecemeal applications of crusading ideas and practices developed primarily in the context of the Church’s crusade experience in the Holy Land. As a result, it acquired the character of what she calls “penitential war” – a form of ecclesiastical war conferring fewer spiritual rewards and less prestige than the crusades to the East. Under Pope Honorius III (1216-27), however, papal policy changed in this respect: largely due to growing papal involvement in the missionary project, during his pontificate the ecclesiastical wars in the Baltic region were decisively elevated to full crusade status with all the same indulgences, privileges and protections as those to the Holy Land. Prior to the pontificate of Innocent III (Honorius’ predecessor), missions had effectively fallen within the purview of the frontier bishops, kings and princes. During the pontificates of Innocent and Honorius, however, the papacy arrogated to itself greater responsibility for initiating and directing large-scale missions among both heretics and pagans – largely as a result of the post-Gregorian papacy’s socially constructed identity and its entailed core interest in active preaching and evangelization (i.e. living the “apostolic life”). Not surprisingly, as the missions became an increasingly important papal priority so too did their defence against those social forces that would violently oppose their evangelizing work.
In practical terms, this had the effect creating two new models for Baltic crusading. During the early phase, expeditions were initiated by local bishops or princes who sought and received papal authorization, but essentially retained control over planning, preaching, financing and other practical matters. As Fonnesberg-Schmidt demonstrates, while this pattern continued throughout the later Middle Ages, it was supplemented from the early 13th century onward by two new forms of crusade. The first of these involved a partnership between the Dominicans and the Teutonic Order in which the former preached and recruited for the crusade and the latter financed and conducted it. The Teutonic Order had been introduced to the region in the 1220s and had subsequently secured from Pope Innocent IV the right to launch expeditions and issue indulgences to those fighting in its ranks without additional papal authorization. In effect, this created a permanent crusade under the leadership of the knights who proceeded to conquer Prussia and Lithuania and establish the Order State of the Teutonic Knights. The second new model involved a more active leadership role for the papal curia. In this type, the initiative for the crusade came from the pope, while its preaching and direction was made the responsibility of a papal legate. The crusade in Livonia proclaimed by Pope Gregory in his 1236 encyclical Ne Terra Vastae is a prime example of this sort of expedition. In both cases, the rationale remained the defence of the missions and their newly converted flocks; the “liberation” of Christians from pagan oppression and pagans from ignorance; and the vindication of injuries done to Christ and His Church . From the early 13th century onward, however, the way in which the Church mobilized its martial resources became more differentiated.
It used to be believed that the Northern Crusades were simply an unremarkable element of the broader historical process of conquest and colonization that has come to be known as the Ostseidlung. On this view, the ecclesiastical wars in the Baltic region were little more than a series of essentially mundane campaigns to acquire fish, fur, and land – campaigns cloaked in a thin religious veil to be sure, but ultimately reducible to the all-too-worldly pursuit of wealth and power. As Housley points out, however, recent research has begun to move in a somewhat different direction. Rather than focusing narrowly on the socio-political determinants of these crusades, researchers have now begun to explore more fully the religious causes and character of these wars. The emerging consensus seems to be that the causes and character of the crusades around the Baltic were informed by the convergence of socio-political and socio-religious factors. On the one hand, there is little doubt that many Christian marcher lords were powerfully motivated to wage war on their pagan neighbours for reasons that had little to do with religion – specifically, the desire to acquire productive land and peasants through a process of violent political accumulation. Similarly, there can be little doubt that the dynamics of state-building were also at play in many of these expeditions. On the other, it is increasingly clear that the key Church officials behind the Northern crusades were motivated primarily by religious concerns and interests, including most importantly the perceived need to create a political context conducive to the peaceful expansion of Christendom through missionary work. It is also clear that many Christian warriors were motivated to wage war not on the basis of worldly concerns, but as a result of their deeply held religious convictions.
Crusades against Christians
Thus far, we have looked at three expressions of religious war along Latin Christendom’s long frontier with the non-Christian world: the crusades to the Holy Land, those in Iberia and those taking place along the Baltic coastline. The final expression or form of religious war, however, was not directed outward against Muslims or pagans, but inward against Christians within Catholic Christendom.
The most notable example of an ecclesiastical war waged against a heretical social movement was that waged against the Cathars or Albigensians in the Languedoc region in what is now southwestern France. The Cathars were a dualist or Manichean sect which rejected almost every element of Latin dogma, liturgical practice and ecclesiastical structure. By the early thirteenth century, the movement had taken hold in areas such as the Rhineland and northern Italy, but was especially pervasive in the Languedoc where it had found favour not only amongst peasants and burghers, but amongst a number of the region’s more influential nobles as well. The reasons for its popularity in this region are complex, but a crucially important factor was the lack of effective political authority in the region. For centuries, the Church had relied on the secular authorities to create the political context within which the Church could carry out its core mission. This included suppressing unorthodox religious movements when they posed a threat to this mission. For most of the preceding nine hundred years, this had not been a particularly pressing problem as most such movements had comprised little more than individual preachers and a handful of followers. In Languedoc, however, Catharism was an increasingly pervasive and institutionalized mass movement – one that threatened to displace Christianity in throughout the region and so inflict grievous injury on both the Church and the respublica Christiana. It was also viewed as an expression of the kind of collective sinfulness that had contributed to the disasters in the Holy Land in 1187 – that is, as a manifestation of the spiritual disorder plaguing Christendom that God had punished by laying low the crusader principalities. It is perhaps not surprising, then, that the Church turned to the temporal authorities – including both Count Raymond VI of Toulouse, the nominal prince of the region, and King Philip of France – to suppress this movement. It was only when it found these powers unable or unwilling to deal with the Cathar threat that it sought alternative remedies.
Catharism had been an issue in the region at least since 1178 when Count Raymond V appealed to the temporal and spiritual authorities for assistance in dealing with the emerging heresy in his domain. The initial response, a Cistercian preaching mission to the region, failed to stem the rising Cathar tide, as did a subsequent military expedition against Roger Trencavel II who was believed to be abetting the heretics. When Innocent III became pope in 1198, he was determined to enforce orthodoxy in the region. Reflecting his own identity as a reform pope, he began his campaign by sending preachers to the region and by taking steps to reform the local Church. When these efforts again failed to yield the hoped-for results, however, Innocent came to the conclusion that he had no option but to suppress Catharism by force. In 1204 he called on Philip of France to come to the aid the Church, promising indulgences to all of the king’s subjects who did their duty to suppress heretical movements. At first, Philip declined to provide the requested aid, largely because he was concerned that King John of England would exploit the opportunity and attempt to recover territories recently lost to France. Innocent repeated his appeal for aid in 1205 and 1207, sweetening the offer by promising all who took the cross the privileges and protections typically associated with a crusade (although none had yet been proclaimed). Philip, however, again declined to act. Frustrated by the failure of the temporal powers to discharge what he perceived to be their duty to aid the Church, Innocent eventually came round to the view that he would have to mobilize his own war-making capabilities to deal with the Cathars. He was able to do nothing militarily, however, until one of his legates, Peter of Castelnau, was murdered in 1208 after excommunicating Raymond VI for failing to take steps to suppress the heresy. Upon hearing of Peter’s death (which he suspected was at Raymond’s hand), Innocent seized the opportunity to mobilize the armed laity of Latin Christendom against the Cathars and those, like Raymond, whom he believed abetted them, by proclaiming a crusade. The response to the call among the nobles of France was “enthusiastic, even fervent” and a large crusader army was quickly dispatched to attack the lands of Raymond Roger Trencavel, Viscount of Béziers and Carcassonne, a suspected Cathar sympathizer. Thus began a brutal two-decades long war in the region – a war that ultimately destroyed the power of the temporal lords who had protected the heretics, leaving the newly created Inquisition a free hand to extinguish Catharism as a threat to Latin Christendom once and for all.
Andrew A. Latham is a Professor and Chair, Political Science Department, Macalester College. He is the author of Theorizing Medieval Geopolitics: War and World Order in the Age of the Crusades and the fictional novel The Holy Lance. You can visit his website at www.aalatham.com
 Given the focus of the existing constructivist literature on the crusades, Appendix 1 provides an account of these religious wars organized around the framework developed here.
 Para-crusaders, or milites ad terminum, served for a fixed amount of time as an act of devotion. See Riley-Smith, The Crusades: A History, 103.
 Key contemporary secondary sources related to the Crusades to the Holy Land include Riley-Smith, The Crusades: A History; Helen Nicholson, The Crusades, Cambridge: Hackett Publishing Company, 2004; Thomas F. Madden, A Concise History of the Crusades, New York: Rowman & Littlefield, 1999; France, The Crusades and the Expansion of Catholic Christendom; Lock, Companion to the Crusades; Christopher Tyerman, God’s War: A New History of the Crusades, Cambridge, MA: Harvard University Press, 2006.
 Christopher Tyerman, God’s War, 660. The authoritative study of the Iberian Crusades in English is Joseph F. O’Callaghan, Reconquest and Crusade in Medieval Spain. Philadelphia: University of Pennsylvania Press, 2003. See also Jean Flori, La guerre saint: La formation de l’idée de croisade dans l’Occident chrétien, Paris: Aubier, 2001. 277-91. For a good overview of the evolution of the historiography of these crusades see Housley, Contesting the Crusades, 100-109.
 O’Callaghan, Reconquest and Crusade in Medieval Spain, 21.
 Tyerman , God’s War, 655; Lock, Companion to the Crusades, 211.
See William Urban, The Baltic Crusade, 2nd ed., Chicago: Lithuanian Research and Studies Center, 1994; Eric Christiansen, The Northern Crusades, 2nd ed., London: Macmillan, 1997; Alan V. Murray, (ed.), Crusade and Conversion on the Baltic Frontier 1150-1500, Aldershot: Ashgate, 2001; Sven Ekdahl, “Crusades and Colonization in the Baltic,” in Helen J. Nicholson (ed.), Palgrave Advances in the Crusades (Houndmills: Palgrave Macmillan, 2005); and Fonnesberg-Schmidt, The Popes and the Baltic Crusades.
 See Christiansen, The Northern Crusades for a different historical schema.
 Although scholars once overwhelmingly viewed this type of war as a distortion or perversion of the institution of the crusade, in recent years it has come to be seen instead as perfectly legitimate extension of that institution – little different, in fact, from its application in Iberia or the Baltic. See Housley,Contesting the Crusades, 115-121.
 Riley-Smith, What Were the Crusades?, 20.
 Ibid., 22.
 Riley-Smith, The Crusades: A History, 297-8.
 Riley-Smith, The Crusades: A History, 2nd ed., New Haven, CT: Yale University Press, 2005, 112-36. For an alternative periodization see Helen Nicholson, The Crusades, Cambridge: Hackett Publishing Company, 2004, 1-20.
 Riley-Smith, The Crusades: A History, 104.
 Riley-Smith, The Crusades: A History, 124.
 More detailed summaries of the Second Crusade include Thomas F. Madden, A Concise History of the Crusades, New York: Rowman & Littlefield, 1999, 57-63; John France, The Crusades and the Expansion of Catholic Christendom, 1000-1714, New York, NY: Routledge, 2005, 130-139; and Riley-Smith, The Crusades: A History, 121-133.
 Riley-Smith, The Crusades: A History, 137-82.
 Ibid., 107.
 More detailed summaries of the Third Crusade include Madden, A Concise History of the Crusades, 65-98; and Riley-Smith, The Crusades: A History, 137-45.
 Riley-Smith, The Crusades: A History, 137.
 Lock, The Routledge Companion to the Crusades, London: Routledge, 2006, 152.
 Madden, A Concise History of the Crusades, 81.
 Lock, Companion to the Crusades, 156.
 Ibid., 158.
 For summary accounts see Lock, Companion to the Crusades, 169-170 and Madden, A Concise History of the Crusades, 155-165.
 Riley-Smith, The Crusades: A History, 183-214.
 O’Callaghan, Reconquest and Crusade in Medieval Spain, Philadelphia: University of Pennsylvania Press, 2003, 23.
 France, The Crusades and the Expansion of Catholic Christendom, 29.
 Tyerman, God’s War: A New History of the Crusades. Cambridge, MA: Harvard University Press, 2006, 658.
 Housley, Contesting the Crusades, Malden, MA: Blackwell Publishing, 2006, 101.
 While some, such as Riley-Smith, have questioned the claim that this was a précroisade, O’Callaghan makes a convincing case that it was. See O’Callaghan, Reconquest and Crusade in Medieval Spain, 24-7.
 Ibid., 27-9.
 O’Callaghan, Reconquest and Crusade in Medieval Spain, 31.
 Tyerman, God’s War, 662.
 Lawrence J. McCrank, Medieval Frontier History in New Catalonia. No. III, Aldershot: Variorum, 1996 as cited in O’Callghan, Reconquest and Crusade in Medieval Spain, 32.
 Lock, Companion to the Crusades, 206, 307.
 O’Callaghan, Reconquest and Crusade in Medieval Spain, 35-6.
 Ibid., 36-8.
 Housley, Contesting the Crusades, 103.
 Ibid., 102-3.
 O’Callaghan, Reconquest and Crusade in Medieval Spain, 44-6.
 Tyerman, God’s War, 667.
 This latter crusade was preceded by the promulgation of a Peace and Truce of God in order to ensure the internal tranquility necessary for a successful campaign against the Muslims. O’Callaghan, Reconquest and Crusade in Medieval Spain, 47.
 Housley, Contesting the Crusades, 105.
 For a discussion of the military religious orders in Iberia, see O’Callaghan, Reconquest and Crusade in Medieval Spain, 55-8 and Tyerman, God’s War, 667-8.
 Tyerman, God’s War, 668; Housley, Contesting the Crusades, 105.
 See Eric Christiansen, The Northern Crusades. 2nd ed., London; Macmillan, 1997 for a different historical schema.
 Giles Constable, Crusaders and Crusading in the Twelfth Century, Burlington, VT: Ashgate Publishing, 2008, 197-204.
 For a translation of this Charter, see Ibid., 211-4.
 Hans-Deitrich Kahl, “Crusade Eschatology as Seen by Saint Bernard in the Years 1146-1148”, as cited in Housley, Contesting the Crusades, 111, fn. 53. Regarding the so-called Sybelline prophesies, see also Fonnesberg-Schmidt, The Popes and the Baltic Crusades, 1147-1254. Boston: Brill, 2007, 28.
 Fonnesberg-Schmidt,The Popes and the Baltic Crusades.
 Christiansen, The Northern Crusades, 65.
 Fonnesberg-Schmidt, The Popes and the Baltic Crusades.
 Christiansen, The Northern Crusades, 65.
 Fonnesberg-Schmidt, The Popes and the Baltic Crusades.
 One year’s remission of sin rather than the plenary indulgences granted by Eugenius in 1147 and typical of the crusades to the Holy Land. Probably in order to make crusades to the Holy Land more appealing, Alexander also offered none of the related privileges and protections. See Fonnesberg-Schmidt,The Popes and the Baltic Crusades, 56-65.
 Urban, The Baltic Crusade, 2nd ed., Chicago: Lithuanian Research and Studies Center, 1994, 25-6.
 Ibid., 27-8.
 Fonnesberg-Schmidt, The Popes and the Baltic Crusades, 72.
 Lock, Companion to the Crusades, 220.
 See Fonnesberg-Schmidt, The Popes and the Baltic Crusades, 183-6.
 Riley-Smith, The Crusades: A History, 197-8.
 Fonnesberg-Schmidt, The Popes and the Baltic Crusades, 193.
 Housley, Contesting the Crusades, 115.
 Although scholars once overwhelmingly viewed this type of war as a distortion or perversion of the institution of the crusade, in recent years it has come to be seen instead as perfectly legitimate extension of that institution – little different, in fact, from its application in Iberia or the Baltic. See Housley,Contesting the Crusades, 115-121.
 Other crusades against heretics include the so-called “Hussite Crusade”, 1420 to c. 1434 and the Waldensian crusade in the Dauphine, 1487-8. See, respectively, Lock Routledge Companion to the Crusades, 201-2 and 204-5.
 For an extended discussion of the nature of Catharism, see Malcom Barber, The Cathars: Dualist Heretics in Languedoc in the High Middle Ages, Harlow: Longman, 2000. For an alternative perspective, see Mark Gregory Pegg, A Most Holy War: The Albigensian Crusade and the Battle for Christendom, Oxford: Oxford University Press, 2008.
 Riley-Smith, The Crusades: A History, 167.