Crusades

The Crusades were a series of military campaigns launched by the papacy between 1095 and 1291 against Muslim rulers for the recovery and defence of the Holy Land (Palestine), encouraged by promises of spiritual reward. The First Crusade was proclaimed by Pope Urban II at the Council of Clermont on 27 November 1095 in response to a Byzantine appeal for aid against the advancing Seljuk Turks. By this time, the papacy's position as head of the Catholic Church had strengthened, and earlier conflicts with secular rulers and wars on Western Christendom's frontiers had prepared it for the direction of armed force in religious causes. The First Crusade led to the creation of four Crusader states in the Middle East, whose defence required further expeditions from Catholic Europe. The organisation of such large-scale campaigns demanded complex religious, social, and economic institutions, including crusade indulgences, military orders, and the taxation of clerical income. Over time, the crusading movement expanded to include campaigns against pagans, Christian dissidents, and other enemies of the papacy, promoted with similar spiritual rewards and continuing into the 18th century.

The Crusade of 1101, the earliest papally sanctioned expedition inspired by the First Crusade, ended in disastrous defeats. For several decades thereafter, only smaller expeditions reached the Holy Land, yet their role in consolidating and expanding the Crusader states was pivotal. The fall of Edessa, the capital of the first Crusader state, prompted the Second Crusade, which failed in 1148. Its failure reduced support for crusading across Latin Christendom, leaving the Crusader states unable to resist Saladin's expansion. Having united Egypt and Muslim Syria under his rule, Saladin destroyed their combined armies at the Battle of Hattin in 1187. The Crusader states survived largely owing to the Third Crusade, a major campaign against Saladin, though Jerusalem remained under Muslim control. Initially directed against Egypt, the Fourth Crusade was diverted to the Byzantine Empire, culminating in the Sack of Constantinople and the establishment of the Latin Empire in 1204. The Fifth Crusade again targeted Egypt but failed to conquer it in 1219–21. By this period, crusade indulgences could also be obtained through other campaigns—such as the Iberian, Albigensian, and Northern Crusades—thereby diminishing enthusiasm for expeditions in the eastern Mediterranean.

Jerusalem was regained through negotiation during the Sixth Crusade in 1229, and in 1239–41 the Barons' Crusade restored much of the territory the Crusader states had lost. However, the Sack of Jerusalem by Muslim freebooters soon ended Crusader rule in the Holy City. Louis IX of France launched two major campaigns—the Seventh Crusade against Egypt in 1248–51 and the Eighth Crusade against Tunis in 1270—both of which ended in failure. In place of the large-scale passagium generale, the smaller passagium particulare became the predominant form of crusading campaigns in the late 13th century. The Crusader states, however, were unable to withstand the advance of the Mamluks. Having reunited Egypt and Muslim Syria by 1260, they went on to attack the Crusader states, capturing the Crusaders' last mainland strongholds in 1291. Although plans for the reconquest of the Holy Land continued to be made in the following decades, only the Alexandrian Crusade briefly revived crusading activity in the region in 1365.

The Crusades were military campaigns undertaken by Western Christians to reclaim the Holy Land, or Palestine, from Muslim control between the 11th and 13th centuries. Launched by the papacy with promises of spiritual reward, they were occasionally accompanied by unauthorised movements—driven by popular zeal—commonly referred to as popular crusades. In scholarly usage, the term is frequently applied more broadly to include papally authorised conflicts in other regions, conducted within the wider framework of the crusading movement, including the Iberian, Northern and Albigensian Crusades.

Terminology evolved gradually, primarily reflecting the close association between the Crusades and Christian pilgrimage. Early usage favoured terms denoting mobility—iter ('journey'), expeditio ('expedition'), passagium ('passage')—typically accompanied by references to the intended destination, such as the Church of the Holy Sepulchre in Jerusalem. Other early expressions invoked the cross (crux), and by around 1250, canon lawyers were distinguishing between campaigns in the Holy Land—crux transmarina ('the cross overseas')—and those within Europe—crux cismarina ('the cross this side of the sea'). Participants, who traditionally sewed a cross onto their garments, came to be known as crucesignati ('those signed with the cross').

Vernacular terminology reflected the ritual of "taking the cross". The earliest attested form, crozada, appeared in Spain in 1212. The Middle English croiserie, derived from Old French, emerged in the 13th–14th centuries, later supplanted by forms such as croisade and crusado, both influenced by Spanish through French. The modern term crusade was established by 1706. The medievalist Thomas Asbridge notes that the term's conventional use by historians imposes "a somewhat misleading aura of coherence and conformity" on the earliest crusading efforts.

Sites linked to Jesus's ministry became popular pilgrimage destinations in Roman Palestine. Christian emperors built churches at these locations, including the Church of the Holy Sepulchre, marking Jesus's crucifixion and resurrection in Jerusalem. In 395, the Roman Empire split into eastern and western halves. The Western Roman Empire had fragmented into smaller kingdoms by 476, while the Eastern Roman (Byzantine) Empire persisted, though it lost vast territories to the rising Islamic Caliphate in the 7th century. Jerusalem fell to Caliph Umar in 638. Islamic expansion, motivated by jihad (holy war), reached Western Europe with the Muslim conquest of much of the Iberian Peninsula after 711. Christians under Muslim rule were dhimmi—legally protected but socially subordinate. Islam's ideological unity fractured over disputes about leadership. The Shi'a believed authority belonged to the descendants of Muhammad's cousin and son-in-law, Ali, while the Sunni majority rejected the Alids' hereditary claim. By the mid-10th century, three rival caliphates had emerged: the Umayyads in al-Andalus (Muslim Spain), the Shi'ite Fatimids in Egypt, and the Abbasids in the Middle East.

To Muslim observers, such as Ibn Khordadbeh, the remote and less developed Western Europe was merely a source of slaves and raw materials. However, between c. 950 and c. 1070, drought and cold spells across North Africa, the Middle East, and Central Asia led to famine and migration. Interfaith tensions escalated, culminating in the temporary destruction of the Holy Sepulchre in 1009. From the 1040s, nomadic Turkomans disrupted the Middle East. In 1055, their leader Tughril I of the Seljuk clan assumed authority within the Abbasid Caliphate with Caliph Al-Qa'im's consent. Tughril's nephew Alp Arslan crushed the Byzantines at the Battle of Manzikert in 1071, opening Anatolia to Turkoman migration. The Seljuk Empire emerged as a loose federation of provinces ruled by Seljuk princes, Turkoman warlords and Arab emirs. As Byzantine control collapsed, Armenian and Greek strongmen took over frontier cities and fortresses.