Council of Clermont in the context of Gothic architecture

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.

The First Crusade (1096–1099) was the first and most successful of a series of religious wars, or Crusades, which were initiated, supported and at times directed by the Latin Church in the Middle Ages. Their aim was to return the Holy Land—which had been conquered by the Rashidun Caliphate in the 7th century—to Christian rule. By the 11th century, although Jerusalem had then been ruled by Muslims for hundreds of years, the practices of the Seljuk rulers in the region began to threaten local Christian populations, pilgrimages from the West and the Byzantine Empire itself. The earliest impetus for the First Crusade came in 1095 when Byzantine emperor Alexios I Komnenos sent ambassadors to the Council of Piacenza to request military support in the empire's conflict with the Seljuk-led Turks. This was followed later in the year by the Council of Clermont, at which Pope Urban II gave a speech supporting the Byzantine request and urging faithful Christians to undertake an armed pilgrimage to Jerusalem.

This call was met with an enthusiastic popular response across all social classes in western Europe. Thousands of predominantly poor Christians, led by the French priest Peter the Hermit, were the first to respond. What has become known as the People's Crusade passed through Germany and indulged in wide-ranging anti-Jewish activities, including the Rhineland massacres. On leaving Byzantine-controlled territory in Anatolia, they were annihilated in a Turkish ambush led by the Seljuk Kilij Arslan I at the Battle of Civetot in October 1096.

Pope Urban II (Latin: Urbanus II; c. 1035 – 29 July 1099), otherwise known as Odo of Châtillon or Otho de Lagery, was the head of the Catholic Church and ruler of the Papal States from 12 March 1088 to his death. He is best known for convening the Council of Clermont, which ignited the series of Catholic military expeditions known as the Crusades.

Pope Urban was a native of France and a descendant of a noble family from the French commune of Châtillon-sur-Marne. Before his papacy, Urban was the grand prior of Cluny and bishop of Ostia. As pope, he dealt with Antipope Clement III, the infighting of various Christian nations, and the Turkish invasions into Anatolia. In 1095, he started preaching for the start of the First Crusade (1096–1099). He promised forgiveness and pardon for all of the past sins of those who would fight to reclaim the Holy Land from Muslims and free the Eastern churches. This pardon would also apply to those fighting the Muslims in Spain. While the First Crusade resulted in the occupation of Jerusalem and expulsion of the Fatimids, Pope Urban II died before he could receive the news.

In the history of the Catholic Church, a crusade indulgence was any indulgence—remission from the penalties imposed by penance—granted to a person who participated in an ecclesiastically sanctioned crusade. It had its origins in the Council of Clermont that closed on 27 November 1095. According to Lambert of Arras, who was present, the council decreed that, "Whoever for devotion alone, not to gain honour or money, goes to Jerusalem to liberate the Church of God can substitute this journey for all penance." This marked the start of the First Crusade. Later popes and councils often invoked "the same remission as instituted by Pope Urban at the council at Clermont." The connection to the liberation of Jerusalem was later weakened and the same or similar indulgence offered to participants in the Northern Crusades and the Albigensian Crusade.

The Crusading movement was a major religious, political and military endeavour of the Middle Ages—began in 1095 when Pope Urban II, at the Council of Clermont, proclaimed the First Crusade to liberate Eastern Christians from Muslim rule. He framed it as a form of penitential pilgrimage, offering spiritual rewards. By then, papal authority in Western Christendom had grown through church reforms, and tensions with secular rulers encouraged the notion of holy war—combining classical just war theory, biblical precedents, and Augustine's teachings on legitimate violence. Armed pilgrimage aligned with the era's Christocentric and militant Catholicism, sparking widespread enthusiasm. Western expansion was further enabled by economic growth, the decline of older Mediterranean powers, and Muslim disunity. These factors allowed crusaders to seize territory and found four Crusader states. Their defence inspired successive Crusades, and the papacy extended spiritual privileges to campaigns against other targets—Muslims in Iberia, pagans in the Baltic, and other opponents of papal authority.

The Crusades fostered distinctive institutions and ideologies, having a great impact on medieval Europe and the Mediterranean. Though aimed primarily at the warrior elite through appeals to chivalric ideals, they depended on broad support from clergy, townspeople, and peasants. Women, despite being discouraged, were involved as participants, proxies for absent crusaders, or victims. Although many crusaders were motivated by indulgences (remission of sins), material gain also played a part. Crusades were typically initiated through papal bulls, with participants pledging to join by "taking the cross"—sewing a cross onto their garments. Failure to fulfil vows could result in excommunication. Periodic waves of zeal produced unsanctioned "popular crusades".

The Iberian Crusades were papally promoted wars, part of the Reconquista, fought against the Muslim states of the Iberian Peninsula within the wider Crusading movement from 1095 to 1492. The Muslim conquest of the peninsula was completed in the early 8th century, when the Christian Visigothic Kingdom fell, yet the small realm of Asturias endured in the north-west. From the 9th century, its southward expansion against al-Andalus (Muslim Spain) was portrayed in local chronicles as a divinely sanctioned war of recovery. This expansion, along with Frankish advance, gave rise to new Christian realms—Navarre, León, Aragon, Castile, Portugal, and Barcelona—in the north. After al-Andalus split into taifas (small states) in 1031, the Christian realms exploited Muslim disunity to further expansion. From the 1060s, the papacy occasionally supported campaigns against al-Andalus by granting spiritual rewards to participants.

As the Reconquista advanced, the taifa rulers sought aid from the fundamentalist Almoravids of North Africa, who halted the Christian expansion. Soon after proclaiming the First Crusade for the liberation of the Holy Land at the Council of Clermont in 1095, Pope Urban II extended the same spiritual privilege—remission of sins—to Iberian lords who took up arms against the Moors (Iberian Muslims). Peter I of Aragon was the first ruler, in 1100, to fulfil his crusading vow within the peninsula, and his example was soon followed by others. Leading crusading armies, Alfonso I of Aragon captured Zaragoza (1118), Afonso I of Portugal seized Lisbon (1147), and Ramon Berenguer IV of Barcelona took Tortosa (1148). The renewed Christian advance provoked another North African intervention, this time by the Almohads, who could only temporarily halt the Christian expansion. Occasionally, the Moors' Christian allies, such as Alfonso IX of León were also targeted by crusading campaigns. After crusader forces inflicted a decisive defeat on the Almohads at the Battle of Las Navas de Tolosa in 1212, the Reconquista gained new momentum. Papal grants of crusade indulgence then supported James I of Aragon in the conquest of Mallorca (1231) and Valencia (1238), and Ferdinand III of Castile in the capture of Córdoba (1236) and Seville (1248), reducing al-Andalus to the Emirate of Granada by 1262.

The siege of Jerusalem marked the successful end of the First Crusade, whose objective was the recovery of the city of Jerusalem and the Church of the Holy Sepulchre from Islamic control. The five-week siege began on 7 June 1099 and was carried out by the Christian forces of Western Europe mobilized by Pope Urban II after the Council of Clermont in 1095. The city had been out of Christian control since the Muslim conquest of the Levant in 637 and had been held for a century first by the Seljuk Turks and later by the Egyptian Fatimids. One of the root causes of the Crusades was the hindering of Christian pilgrimages to the Holy Land which began in the 4th century. A number of eyewitness accounts of the battle were recorded, including in the anonymous chronicle Gesta Francorum.

After Jerusalem was captured on 15 July 1099, thousands of Muslims and Jews were massacred by Crusader soldiers. As the Crusaders secured control over the Temple Mount, revered as the site of the two destroyed Jewish Temples, they also seized Al-Aqsa Mosque and the Dome of the Rock and repurposed them as Christian shrines. Godfrey of Bouillon, prominent among the Crusader leadership, was elected as the first ruler of Jerusalem.

Gesta Francorum (Deeds of the Franks), or Gesta Francorum et aliorum Hierosolimitanorum (Deeds of the Franks and the other pilgrims to Jerusalem), is the name given to one of a family of Latin narrative accounts of the First Crusade. Its simplicity, relative brevity, and similarity to a number of other Latin accounts of the crusade have led scholars to advance a number of theories about the work's authorship, date, and relationship to the larger corpus of Latin crusade chronicles. Although it is still often cited as a stand-alone account of a single author, there is little agreement about the context or authorship of the work nor its exact place within the corpus. Its status as a very early account of the events, informed directly by the experiences of those that took part, is unquestioned. It remains one of the most important sources for the history of the First Crusade.

The Gesta Francorum (often shortened to "the Gesta") narrates the events of the First Crusade from the time of its initial preaching by Pope Urban II in 1095 to the first Battle of Ascalon on 12 August,1099. As an account of a single event, it is a revolutionary book. As Jay Rubenstein has observed "in 1100, histories of single events were rare, almost unheard of." Compared to other narratives of the expedition, it is a short work of only about 20,000 words, divided in most manuscripts into ten books. The work's most recent editor, Rosalind Hill, called the style "extremely terse, simple, and unadorned." Notably, the account makes no direct reference to the Council of Clermont (17-27 November, 1095) instead alluding to the preaching of the pope in France more generally. It begins, strikingly, with a reference to the words of Jesus Christ in Matthew 16:24

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, encouraged by promises of spiritual reward. The First Crusade was proclaimed by Pope Urban II at the Council of Clermont in November 1095, a call to arms for Christians to reconquer Jerusalem from the Muslims. 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 successes of 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.

The Crusading movement was a major religious, political, and military endeavour of the Middle Ages, traditionally dated from 1095, when Pope Urban II, at the Council of Clermont, proclaimed an armed expedition by Western Christendom in support of Eastern Christians under Muslim rule. He framed it as a form of penitential pilgrimage, offering spiritual rewards. By then, papal authority had grown through church reforms, and tensions with secular rulers encouraged the notion of holy war—combining classical just war theory, biblical precedents, and Augustine's teachings on legitimate violence. Armed pilgrimage aligned with the era's Christocentric and militant Catholicism, sparking widespread enthusiasm. Western expansion was further enabled by economic growth, the decline of older Mediterranean powers, and Muslim disunity. These factors allowed crusaders to seize territory and found four Crusader states. Their defence inspired successive Crusades, and the papacy extended spiritual privileges to campaigns against other targets—Muslims in Iberia, pagans in the Baltic, and other opponents of papal authority.

The papal-sanctioned wars fostered distinctive institutions and ideologies, having a great impact on medieval Europe and the Mediterranean. Though aimed primarily at the warrior elite through appeals to chivalric ideals, they depended on broad support from clergy, townspeople, and peasants. Women, despite being discouraged, were involved as participants, proxies for absent crusaders, or victims. Although many crusaders were motivated by indulgences (remission of sins), material gain also played a part. Crusading campaigns were typically initiated through papal bulls, with participants pledging to join by "taking the cross"—sewing a cross onto their garments. Failure to fulfil vows could result in excommunication. Periodic waves of zeal produced unsanctioned "popular crusades".

Albert of Aix(-la-Chapelle) or Albert of Aachen; Latin: Albericus Aquensis; fl. c. 1100) was a historian of the First Crusade and the early Kingdom of Jerusalem. He was born during the later part of the 11th century, and afterwards became canon (priest) and custos (guardian) of the church of Aachen.

Nothing else is known of his life except that he was the author of a Historia Hierosolymitanae expeditionis (“History of the Expedition to Jerusalem”), or Chronicon Hierosolymitanum de bello sacro, a work in Latin in twelve books, written between 1125 and 1150. This history begins at the time of the Council of Clermont in 1095, deals with the fortunes of the First Crusade and the earlier history of the Latin Kingdom of Jerusalem, and ends somewhat abruptly in 1121.