The Crusades: A Complete History of the Medieval Holy Wars

In December 1098, the Muslim chronicler Ibn al-Qalanisi of Damascus noted in his diary that a “Frankish host” had appeared out of nowhere, captured Antioch, and was marching south. “They were a people,” he wrote, “who had suddenly appeared from an unknown region, with no known origin or religion.” It was, for him, the start of a catastrophe. For the peasants of the Île-de-France who had taken the cross at Clermont the year before, it was a journey home.

The Crusades, in other words, looked utterly different depending on which side of the Mediterranean you were standing on. Two centuries of religious warfare followed, in which armies that almost never numbered more than 30,000 men set fire to the medieval Near East and reshaped Christendom at home. This article tries to give the movement as a whole in something like 5,000 words. Readers who want a particular expedition in depth will find links throughout to the dedicated pillar pages on the First Crusade, the Second, the Third, the Fourth, and the rest.

One word of editorial framing before the narrative: the older view, popularised by Steven Runciman’s three-volume A History of the Crusades (1951–54) and still common in textbooks, was that the Crusades were a single, ill-fated, ultimately futile project. The newer view, associated above all with Jonathan Riley-Smith and his students, is that the Crusades were a working institution — a permanent passagium — and that they reshaped European political thought, military practice, and colonial governance for centuries. Both readings have something to say. The first is right about the carnage; the second is right about the durability.

Before Clermont: what was actually going on in 1095

The conventional list of Crusades to the Holy Land is:

  1. The First Crusade (1096–1099) – Called by Pope Urban II, culminating in the capture of Jerusalem.
  2. The Second Crusade (1147–1149) – Preached by Bernard of Clairvaux after the fall of the County of Edessa.
  3. The Third Crusade (1189–1192) – Launched in response to Saladin’s conquest of Jerusalem.
  4. The Fourth Crusade (1202–1204) – Famously diverted to sack Constantinople.
  5. The Children’s Crusade (1212) – A mysterious movement of young people, possibly real, possibly mythic.
  6. The Fifth Crusade (1217–1221) – Aimed at Egypt, ended in failure.
  7. The Sixth Crusade (1228–1229) – A diplomatic mission led by Frederick II that briefly recovered Jerusalem.
  8. The Seventh Crusade (1248–1254) – Led by Louis IX of France against Egypt.
  9. The Eighth Crusade (1270) – Also led by Louis IX, this time against Tunis.
  10. The Ninth Crusade (1271–1272) – The future Edward I of England’s campaign in the Holy Land.

For a more detailed chronological account, see the Timeline of the Crusades.

To make any of this make sense, you have to back up to the 1070s. The Seljuk Turks had taken Jerusalem in 1076, and they had rolled the Byzantines back at the catastrophic Battle of Manzikert in 1071. Christian pilgrimage to the Holy Land, which had been the great devotional activity of the eleventh century, became a dangerous undertaking. In 1095 the Byzantine Emperor Alexios I Komnenos sent an embassy to the new reform-pope Urban II asking for mercenaries. Urban, who was then in France trying to recover from the schism with Clement III and the Holy Roman Empire, had a different idea: a popular expedition under papal sponsorship, with the remission of sins as its bait.

What he did not anticipate, and what made the First Crusade the strangest of all the medieval Crusades, was how large the response was. The knightly armies that gathered in 1096 were one thing — perhaps 30,000 men in disciplined regional contingents. The People’s Crusade that set out ahead of them, led by Peter the Hermit and Walter Sans-Avoir, was quite another. It was a poor people’s migration. It ended in slaughter in Civetot in October 1096. The main army, by contrast, succeeded — Antioch fell in June 1098, Jerusalem in July 1099, and the Crusader States were born.

The First Crusade and the foundation of Outremer (1096–1099)

The First Crusade is the only one that genuinely achieved its stated objective. It is also the only one whose chroniclers were mostly eyewitnesses. The result is an unusually rich set of sources, and the modern scholarship on it is unusually good. The best short account is still Jonathan Riley-Smith’s The First Crusade and the Idea of Crusading (1986); Thomas Asbridge’s The First Crusade: A New History (2004) is the best narrative.

The two best eyewitness accounts are Raymond of Aguilers and Fulcher of Chartres. Raymond was a Provençal priest attached to the army of Count Raymond of Toulouse; Fulcher was a northern French cleric who went with the contingent of Stephen of Blois and Robert of Normandy, and whose prose is the calmest of the group. Their accounts of the capture of Jerusalem in July 1099 are the standard sources, and they were both physically present in the city. Raymond, in particular, is famous for the line about the Crusaders wading in blood “up to their ankles” — a description he then walked back, noting that the blood must have been deeper than that. Modern historians treat the figure as a flourish; the underlying fact of a large-scale killing of the Muslim and Jewish inhabitants of the city is not in doubt.

The success of the First Crusade produced the four Crusader States: the Kingdom of Jerusalem, the County of Tripoli, the Principality of Antioch, and the County of Edessa. The standard English-language history of the Kingdom is Joshua Prawer’s The Latin Kingdom of Jerusalem (1972); it is still the place to start, although Prawer’s “colonial” reading has been challenged by more recent work, notably that of Ronnie Ellenblum and Benjamin Kedar.

The Second Crusade: the moment the ideal cracked (1147–1149)

The Second Crusade is in some ways the more interesting failure, because it was the first time the expeditionary model of the First was run at scale. The preaching of Bernard of Clairvaux drew kings Louis VII of France and Conrad III of Germany into the field, with the result that the two largest royal armies since Charlemagne set out across Anatolia and were systematically destroyed by the Seljuks. The collapse at the Siege of Damascus in 1148 was the most embarrassing moment in the history of medieval Christendom.

The Second Crusade is also the first Crusade to leave a substantial Latin historiography on the Christian side and the first to leave an essentially sympathetic Latin historiography. Joinville’s Life of Saint Louis is later, but the model of a French king who saw the Crusade as a form of personal penitence and personal holiness — and was willing to put that vision into operation even when it was tactically disastrous — is firmly established by the second generation. The standard modern study is Jonathan Phillips’s The Second Crusade: Extending the Frontiers of Christendom (2007); older readers will know Hans Mayer’s Geschichte der Kreuzzüge and Steven Runciman’s chapter.

The Third Crusade: the most glamorous of them all (1189–1192)

The Third Crusade is the one people actually remember. It featured three of the most powerful rulers of the age — Emperor Frederick Barbarossa of Germany, King Philip II of France, and King Richard I of England — and it pitted Richard against Saladin in a duel that became the central romance of the medieval West. (Walter Scott’s The Talisman (1825) is the source most English readers carry around; Scott is wonderful but not always reliable.) The expedition is also the first to leave a recognisably modern body of work: Gillingham’s biography of Richard (1978), Phillips’s biography of Richard (2015), Lyons and Jackson on Saladin (1982), and the recent general work by Madden.

The expedition failed in its central objective — Jerusalem was not retaken — but it produced two real achievements. First, the Treaty of Jaffa in 1192 (the most underrated document in medieval history) left a strip of coastline in Christian hands for another century and gave Western pilgrims the right to visit the Holy Sepulchre without paying a tax. Second, it established a diplomatic and military relationship between the Latin West and the Ayyubid East that was based on mutual respect rather than mutual contempt, and that had a real, mostly positive, effect on the treatment of prisoners and pilgrims in the years that followed.

The Fourth Crusade and the Latin Empire (1202–1261)

The Fourth Crusade is the controversy. What began as a major expedition to recapture Jerusalem through Egypt was, through a series of debts, political deals, and one very old Doge of Venice, diverted first to the Adriatic port of Zara in 1202 and then to Constantinople in 1203. The sack of the city on 12–15 April 1204 was, as Jonathan Phillips has put it, “one of the great crimes of European history.” It established the Latin Empire of Constantinople and fatally weakened Byzantium, with consequences that lasted until the fall of the city to the Ottomans in 1453.

The historiography is split into roughly three positions. The older view, going back to Gibbon, was that the diversion was the result of Venetian commercial greed. The view associated with Thomas Madden’s Enrico Dandolo and the Rise of Venice (2003) and Phillips’s The Fourth Crusade and the Sack of Constantinople (2004) is that the decision was made under impossible financial pressure, with several bad options and no good ones. The position associated with Donald Queller’s The Fourth Crusade: The Conquest of Constantinople (1977) is somewhere in between: the Venetians did not plan the diversion, but they exploited it. All three readings have merit; the truth is that the diversion was a sequence of contingent decisions, not a single grand design.

The later Crusades (1217–1272) and the Mamluks

The Fifth through Ninth Crusades are sometimes dismissed as footnotes, which is unfair. The Sixth Crusade, led by Frederick II, was the only one to recover Jerusalem by negotiation, and it did so in 1229. Frederick, who had been excommunicated by the Pope and was on his way to his own Italian war, walked into the Holy City under a treaty of friendship with the sultan al-Kamil, was received politely, crowned himself King of Jerusalem in the Church of the Holy Sepulchre, and walked out again. Pope Gregory IX, predictably, was furious. The Seventh and Eighth Crusades, both led by Louis IX of France, were personal acts of penitence: the king’s piety was real, his strategic judgment was poor, and his death in Tunis in 1270, on the Eighth Crusade, is one of the more poignant ends in medieval history.

What finally broke the Crusader States was the rise of the Mamluk Sultanate in Egypt. The Mamluks were slave-soldiers of mostly Kipchak and Circassian origin who took power in 1250 and immediately turned their attention to Acre, the last major Christian port. The Acre garrison held out through the early 1280s under the kings of Cyprus, but the city fell in May 1291, and the last Christian foothold on the mainland disappeared within weeks. The standard English-language account of the Mamluk wars against the Crusader States is Reuven Amitai-Preiss, Mongols and Mamluks (1995); for the Mamluk state itself, David Ayalon’s many articles are still indispensable.

The military religious orders

The three great military religious orders were, in order of foundation: the Knights Hospitaller, founded in 1099; the Knights Templar, founded around 1119; and the Teutonic Knights, founded in 1190. All three were, in their mature form, religious houses with a military mission; all three developed substantial economic and political interests; and all three had dramatic fates — the Templars were suppressed in 1312 by Pope Clement V at the request of Philip IV of France, the Hospitallers went on to rule Rhodes and then Malta, and the Teutonic Knights went on to wage a long and very violent campaign of conquest in the Baltic, ending in a decisive defeat at the Battle of Grunwald in 1410.

A word about the standard narratives of the orders. The standard history of the Templars is Malcolm Barber’s The New Knighthood (1994); his earlier The Trial of the Templars (1978) remains the definitive account of the suppression. For the Hospitallers, Jonathan Riley-Smith’s The Knights of St John in Jerusalem and Cyprus, 1050–1310 (1967) is the place to start. For the Teutonic Knights, William Urban’s The Teutonic Knights: A Military History (2011) and Eric Christiansen’s The Northern Crusades (1980) are the two best single-volume treatments.

The Muslim response

The Crusades are usually told as a Christian story, which is a mistake. The Muslim response, often unified under charismatic leaders, was a defining factor in the wars’ outcome. The most famous of these leaders is Saladin, the Kurdish founder of the Ayyubid dynasty whose capture of Jerusalem in 1187 set the stage for the Third Crusade. The 19th-century view of Saladin as a chivalrous adversary of Richard the Lionheart is partly a Western construction, but it has a real basis: Saladin was, by the standards of his time, an unusually humane conqueror, and the Muslim sources (especially Baha al-Din ibn Shaddad, his personal secretary) are unusually free of triumphalism about the killing at Jerusalem. The standard modern study is still Lyons and Jackson’s Saladin: The Politics of the Holy War (1982). Other major Muslim figures include Zengi, Nur ad-Din, the Ayyubid princes, and the Mamluk sultans Baibars and Qalawun, who dismantled the remaining Crusader States in the late 13th century. The Muslim response is examined in greater detail in the Saladin and the Muslim World article.

Beyond the Holy Land: the other Crusades

The Crusades were not only about Jerusalem. The papacy and the great military orders waged other holy wars across the medieval world, and these campaigns are usually considered part of the same broad movement.

The Northern Crusades were a series of campaigns by the Teutonic Knights, the Sword Brethren, and others against the pagan peoples of the Baltic region. Beginning in the 12th century and continuing well into the 14th, these wars resulted in the Christianization of Prussia, Livonia, and (much later) Lithuania. The Battle of Grunwald in 1410 marked a decisive check on Teutonic power. The Northern Crusades are, by modern standards, the most ethically difficult chapter of the movement, and they are the chapter that the modern German state has had the most trouble with. The best single book is still Christiansen’s The Northern Crusades.

The Reconquista was the centuries-long effort by the Christian kingdoms of northern Iberia to recapture the peninsula from the Moors. Beginning shortly after the Islamic conquest in 711 and culminating in the fall of Granada in 1492, the Reconquista was a parallel crusade that produced its own military orders (Santiago, Calatrava, Alcántara) and a unique culture of frontier warfare. The standard English-language study is Joseph O’Callaghan’s Reconquest and Crusade in Medieval Spain (2003).

The Albigensian Crusade (1209–1229) was launched against the Cathars of southern France, a Christian group the papacy declared heretical. The campaign was notable for its brutality and for the political interests of the French crown in suppressing the independent south. The standard study is Malcolm Barber’s The Cathars (2000).

What was it actually like?

The standard histories tend to focus on the high politics — the kings, the popes, the treaties, the sieges. The human experience of the Crusade was different, and harder to recover. The march from Europe to the Levant usually took a year, and most of the people who set out did not return. The army of the First Crusade lost perhaps two-thirds of its effective strength between leaving Europe and reaching Antioch. Discipline was a serious problem, especially in the early expeditions: in 1098 the Crusaders besieged and destroyed the Christian city of Ma’arrat an-Numan, and the Muslim chronicler Ibn al-Athir recorded the cannibalism that followed in tones of uncharacteristic horror.

Religious life on Crusade was intense. Mass was celebrated whenever a priest was available, and processions were organized before battles. The discovery of the Holy Lance at Antioch in 1098, almost certainly a fabrication, was a celebrated event that lifted morale. Miracles were eagerly reported and believed. Letters sent home often described the Crusade as an eschatological struggle, a final battle between good and evil. Apocalyptic expectation in the years around the millennium had not been as widespread as older historians believed, but the recapture of Jerusalem was nevertheless seen by many as a sign that the Last Days were at hand. The theology of the Crusades cannot be understood without this apocalyptic backdrop.

The legacy

The Crusades left a deep mark on both Christian and Muslim civilizations. Economically, they accelerated the rise of the Italian mercantile cities. Venice, Genoa, and Pisa grew rich on the trade that the Crusader States generated. Culturally, the Crusades produced a vast literature in Latin, French, Italian, German, and Arabic: chronicles by William of Tyre, Joinville, and Ibn al-Qalanisi remain essential primary sources, while romances from Tasso’s Gerusalemme Liberata to Walter Scott’s The Talisman kept the memory alive. Religiously, the Crusades shaped the theology of just war in both traditions and produced the military religious orders whose successors, including the Sovereign Military Order of Malta, still exist.

Modern historians have revised the older view that the Crusades were a single coherent movement. They are better understood as a series of overlapping campaigns, each with its own logic and character. The First Crusade was a response to the Byzantine appeal and produced the Crusader States. The Second Crusade was a response to the loss of Edessa. The Third Crusade was a response to the loss of Jerusalem. The Fourth Crusade was a Venetian financial operation that produced the Sack of Constantinople in 1204. The Children’s Crusade of 1212 was something else entirely, a popular movement that remains mysterious. The later Crusades were increasingly driven by the strategic concerns of the Italian maritime republics, the ambitions of French and English kings, and the desperate defense of shrinking Crusader territory against the rising Mamluk Sultanate.

What holds these campaigns together is the cross itself, the symbol that all participants wore on their garments, and the idea that participation earned spiritual merit. The cross also gave the movement its name, which is why historians still refer to these wars, with all their diversity, as the Crusades.