The Crusading Movement: Religious Campaigns across Medieval Europe and the Mediterranean

The crusading movement began in the late eleventh century with an armed expedition to the eastern Mediterranean, but it did not remain confined to Jerusalem or to one kind of war. Popes and other church authorities came to authorize campaigns in the Holy Land, Iberia, the Baltic region and within Christian Europe. Their goals, participants and methods changed over time, while the movement’s promise of spiritual reward continued to connect campaigns that otherwise differed greatly. The loss of the last major Latin strongholds on the mainland of the eastern Mediterranean in 1291 ended one phase, not crusading as a whole: campaigns and proposals continued into the early modern period.

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What crusading meant

People who joined early expeditions described them as journeys, pilgrimages or military passages. The familiar English term came into use later. A participant who vowed to go on a campaign could “take the cross”: the cross sewn onto clothing marked a religious vow and a new, temporary status in the church’s eyes.

That status brought spiritual and practical benefits. A crusade indulgence offered remission of the penance prescribed for sin; it was not simply a guarantee of salvation. Church authorities could also place a participant’s family and property under protection and restrict creditors and relieve crusaders of interest charges during the expedition. Over the twelfth and thirteenth centuries, popes extended the spiritual benefits associated with crusading to people who contributed money or other forms of support, not only to those who travelled to fight.

Faith was central to many participants’ understanding of their vows, but it did not exclude other aims. Noblemen might seek to defend or acquire territory, rulers might pursue political advantage, and maritime cities could negotiate commercial privileges in return for transport or naval assistance. These interests could reinforce one another or come into conflict. A campaign proclaimed for one purpose could also be redirected by military setbacks, disputes among its leaders or the political ambitions of its allies.

Origins and the First Crusade

In 1095, Byzantine Emperor Alexios I Komnenos sought military help from the West as Seljuk power threatened Byzantine lands in Anatolia. At the Council of Clermont that November, Pope Urban II called for an armed expedition. His appeal connected assistance to eastern Christians with the journey to Jerusalem and its Christian holy places. It also offered spiritual reward to those who took part. Jerusalem had long been a destination for Christian pilgrims, and the combination of pilgrimage, penance and armed service gave the expedition a distinctive religious character.

The response came from different parts of western Latin Christendom. Some groups of poor people and townspeople set out before the main forces, encouraged by popular preachers. Their journeys were difficult to control: one group plundered while crossing Hungary, and attacks on Jewish communities in the Rhineland in 1096 killed many people. Some church leaders tried to protect Jewish communities, especially local bishops who offered shelter. These early groups departed before the main noble-led contingents and often lacked their resources and command structures.

The nobles and their followers had to pay for a costly journey, often using loans, donations or the sale of property. Their armies travelled through Byzantine territory and into Anatolia, where negotiations with Alexios over territory recovered from the Seljuks caused friction. The crusaders captured Jerusalem in 1099 after a siege. The conquest involved the killing of many of the city’s inhabitants. Some participants returned home after fulfilling their vows; others remained and established Latin-ruled territories, including the Kingdom of Jerusalem, the Principality of Antioch and the County of Tripoli. Their new position created a continuing need for soldiers, supplies and help from Europe.

Holy Land campaigns after 1099

Later expeditions responded to changing circumstances in the eastern Mediterranean rather than following one continuous plan. The capture of Edessa by the ruler Zengi in 1144 prompted the Second Crusade. Its armies travelled from Europe under the leadership of major nobles and rulers, but the campaign ended in failure, including an unsuccessful siege of Damascus in 1148. The defeat did not end the movement, but it exposed the difficulty of coordinating large armies over long distances and of agreeing on priorities with the rulers of the Latin territories.

In 1187, Saladin’s forces defeated the Kingdom of Jerusalem’s army at Hattin and took Jerusalem. The Third Crusade brought new forces to the region. It recovered Acre in 1191 and established a truce that allowed Christian pilgrims to visit holy places, but it did not retake Jerusalem. The Latin presence on the mainland thereafter depended increasingly on coastal strongholds and maritime connections.

Later campaigns tested different approaches. The Fifth Crusade attacked Egypt, capturing the port of Damietta in 1219, but the army failed in its advance towards Cairo and withdrew in 1221. Emperor Frederick II’s expedition in 1228–29 relied instead on negotiation with the Egyptian ruler al-Kamil. A treaty returned Jerusalem and other places to Christian rule for a limited period while preserving Muslim control of important shrines on the Temple Mount. In 1239–41, another expedition restored territory through agreements with divided Muslim rulers. Jerusalem was lost again in 1244.

Louis IX of France led a major campaign against Egypt in 1248–54. The crusaders took Damietta but were defeated on the advance towards Cairo, and Louis was captured before being released. He remained in the region for several years, helping strengthen coastal defences, but subsequent campaigns could not prevent the steady loss of Latin strongholds to the Mamluks, Egypt’s military ruling elite. Acre fell in 1291, followed soon by the remaining mainland strongholds. Proposals to recover the Holy Land continued, and crusaders briefly captured and sacked Alexandria in 1365, but they did not restore lasting Latin rule on the mainland.

Crusading and Byzantium: aid, conflict and 1204

Relations between Latin crusaders and the Byzantine Empire were shaped by overlapping aims and distrust. Alexios I had sought military assistance, but Byzantine emperors also needed to protect their own territory and manage the passage of large, difficult-to-supply armies. During the First Crusade, the Byzantines took possession of Nicaea after its surrender. Disagreements over whether other recovered lands should also be returned to the empire contributed to worsening relations.

The Fourth Crusade shows how far an expedition could move from its announced destination. Its leaders had contracted with Venice for a fleet but could not pay the agreed cost. They agreed to attack Zara, a Christian city on the Adriatic, to meet their debt. The expedition then accepted an offer from Alexios Angelos, who sought to regain the Byzantine throne and promised money and military support. In 1204, after further conflict in Constantinople, the crusaders captured and sacked the city instead of continuing to the Holy Land. They seized wealth and relics and established a Latin Empire over part of the former Byzantine lands.

The conquest did not create the lasting support for the eastern crusader states that its proponents had promised. It deepened the division between Latin Christians and the Orthodox Christians of Byzantium, and the new Latin rule faced resistance. The new Latin Empire lasted until Nicaean forces recovered Constantinople in 1261.

Crusading in Iberia

Crusading privileges were also applied to campaigns in Iberia, where Christian rulers expanded into territories governed by Muslim powers. This process, often called the Reconquista, was not simply a series of expeditions arriving from elsewhere: Iberian rulers pursued their own territorial and political aims. The pope included Iberian campaigns among the causes that could receive spiritual rewards, particularly as attention and recruits were divided among several theatres of war.

In 1147, crusaders travelling by sea helped the Portuguese ruler Afonso I capture Lisbon. In 1212, Christian forces defeated the Almohads at Las Navas de Tolosa in a campaign promoted with crusading support. The advance continued under Iberian kingdoms over the following centuries, ending with the conquest of Granada by Castile and Aragon in 1492. Thus crusading became associated with a long regional struggle as well as with overseas expeditions to the eastern Mediterranean.

Northern and Baltic crusades

From the twelfth century, papal authorization and crusade rewards also supported campaigns in northern Europe. In 1147, the pope extended crusade privileges to a campaign against the pagan Wends in the Baltic region. It formed one of the theatres of the Second Crusade, but did not achieve its military aims.

Campaigns against pagan Prussians followed in the thirteenth century, with the Teutonic Knights taking command in 1230. These wars drew participants from several parts of western Europe and continued into the fifteenth century. Their setting and declared aims differed from expeditions to Jerusalem, but papal backing and the spiritual privileges attached to taking the cross connected them to the wider movement.

Crusades within Christian Europe

Crusading was not limited to campaigns against Muslim rulers or non-Christian peoples. In 1208, Pope Innocent III called for a crusade against the Cathars, a religious movement in southern France that church authorities condemned as heretical. The conflict combined religious aims with struggles over local power and territory. The main military phase ended in 1229, but inquisitorial prosecution and later sieges continued, including Montségur in 1244.

Papal authorities also authorized campaigns against political opponents, dissident Christians and rebels. In such cases, spiritual rewards and church funds could support wars within Europe. This widening of crusading targets prompted criticism, particularly when a campaign seemed remote from the defence or recovery of the Holy Land. It also meant that rulers, nobles and potential recruits could choose among several causes. A call to fight in one region could compete with an expedition elsewhere, even when each was presented as a religious duty.

Later crusading and wars against the Ottomans

The loss of Acre in 1291 did not end the use of crusading as a political and religious framework. Leaders continued to propose new expeditions, while smaller campaigns and wars in other regions carried on. A French and Burgundian army joined forces from Hungary in an invasion of Ottoman territory in 1396, but was defeated at Nicopolis. Crusading in Iberia continued until the fall of Granada in 1492, and the Teutonic Knights’ wars in the Baltic drew western European participants into the fifteenth century.

After the Reformation, the papacy occasionally granted crusade indulgences for campaigns against Protestants. It more often supported Holy Leagues, alliances of Catholic powers formed to fight the Ottomans. Such leagues continued into the seventeenth century. The causes and political settings had changed, but popes and rulers could still invoke crusading language, spiritual rewards or the defence of Christian communities to rally support.

Modern reception

Modern uses of crusading history belong to a later period than the campaigns themselves. The word became established as a broad historical label after the medieval era, and later accounts helped shape national and religious stories about the past. In modern political writing, some Muslim thinkers and politicians have compared crusading with Western imperialism or with events such as the establishment of Israel in 1948. Some right-wing movements in the West have used crusader symbols and language to present Islam as a threat to Christianity. Their purposes range from national commemoration to imperial analogy and modern political mobilisation.