The Crusades

Tales of intrigue, religious fervour, and betrayal. That’s a basic summary of the Crusades! Nonetheless, in this article, we will dig deeper. We will analyse the reasons and origins of each of the Four Crusades, the key events of each Crusade, and their implications.

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Table of contents

    The Crusades were a series of religiously motivated campaigns to recapture the Holy Lands of the Middle East, especially Jerusalem. They were initiated by the Latin Church and, although initially noble in nature, became increasingly motivated by the desire of the West to achieve economic and political power in the East. This was most notably seen in the attack on Constantinople during the Fourth Crusade in 1203.

    CrusadeA religiously motivated war. The term crusade refers specifically to the Christian faith, and the wars initiated by the Latin Church. This was because the fighters were seen as taking up the cross in the same way that Jesus Christ carried his cross in Golgotha before he was crucified.
    East-West Schism of 1054The East-West Schism of 1054 refers to the separation of the Western and Eastern churches led by Pope Leo IX and Patriarch Michael Cerularius respectively. They both excommunicated each other in 1054 and that meant that either church ceased to recognise the validity of the other.
    Papal bullA public decree issued by the Pope.
    Seljuk TurksThe Seljuk Turks belonged to the Great Seljuk Empire which emerged in 1037. As the empire grew they became increasingly antagonistic to the Byzantine Empire and the crusaders as they all wanted control of the lands around Jerusalem.
    Gregorian ReformA vast movement to reform the Catholic Church which started in the eleventh century. The most relevant part of the reform movement is that it reaffirmed the doctrine of Papal Supremacy (which you will find explained below).

    Causes of the Crusades

    The Crusades had multiple causes. Let's explore them.

    The division of Christianity and the ascendancy of Islam

    Since the founding of Islam in the seventh century, there had been religious conflict with the Christian nations to the east. By the eleventh century, Islamic forces had reached as far as Spain. The situation in the Holy Lands of the Middle East was also worsening. In 1071 the Byzantine Empire, under Emperor Romanos IV Diogenes, lost at the Battle of Manzikert to the Seljuk Turks, leading to the loss of Jerusalem two years later in 1073. This was considered unacceptable, as Jerusalem was the place where Christ performed a lot of his miracles and the place where he was crucified.

    In the eleventh century, specifically the period 1050-80, Pope Gregory VII initiated the Gregorian Reform, which argued for Papal supremacy. Papal Supremacy was the idea that the Pope should be considered Christ’s true representative on earth and thus have supreme and universal power over the whole of Christianity. This reform movement increased the power of the Catholic Church and the Pope became more assertive in his demands for Papal Supremacy. In actuality, the doctrine of Papal supremacy was present since the sixth century. Nonetheless, Pope Gregory VII’s argument for it made demands for the doctrine’s adoption particularly strong in the eleventh century.

    This created conflict with the Eastern Church, which viewed the Pope as merely one of the five patriarchs of the Christian Church, alongside the Patriarchs of Alexandria, Antioch, Constantinople, and Jerusalem. Pope Leo IX sent a hostile legation (a diplomatic minister whose rank is lower than that of an ambassador) to the Patriarch of Constantinople in 1054, which led to mutual ex-communication and the East-West Schism of 1054.

    The Schism would leave the Latin Church with a long-running discontent against the Byzantine Kings of the East and monarchical power in general. This was seen in the Investiture Controversy (1076) where the Church argued adamantly that the monarchy, Byzantine or not, should not have the right to appoint church officials. This was a clear difference with the Eastern Churches that generally mostly accepted the power of the Emperor, thus exemplifying the effects of the Schism.

    The Council of Clermont

    The Council of Clermont became the major catalyst of the First Crusade. Byzantine Emperor Alexios Komnenos I was apprehensive about the safety of the Byzantine empire following their defeat at the Battle of Manzikert to the Seljuk Turks, who had reached as far as Nicaea. This concerned the Emperor because Nicaea was very close to Constantinople, the power centre of the Byzantine Empire. As a result, in March 1095 he sent envoys to the Council of Piacenza to ask Pope Urban II to militarily assist the Byzantine Empire against the Seljuk Dynasty.

    Despite the recent schism, Pope Urban responded favourably to the request. He was hoping to heal the schism of 1054 and reunite the East and West Churches under Papal supremacy.

    In 1095, Pope Urban II returned to his native France to mobilise the faithful for the Crusade. His trip culminated in the ten-day Council of Clermont where on 27 November 1095 he gave an inspiring sermon to nobles and clergy in favour of religious war. Pope Urban stressed the importance of charity and helping the Christians of the East. He advocated for a new kind of holy war and reframed the armed conflict as a way to peace. He told the faithful that those who died in the Crusade would go directly to heaven; God had approved the crusade and was on their side.

    Theology of war

    Pope Urban’s urge to fight was met with a lot of popular support. It might seem odd to us today that Christianity would align itself with war. But at the time, violence for religious and communal purposes was common. Christian theology was strongly linked to the militarism of the Roman empire, which had previously ruled the territories now occupied by the Catholic church and the Byzantine Empire.

    The doctrine of Holy War dates back to the writings of St Augustine of Hippo (fourth century), a theologian who argued that war could be justified if it was sanctioned by a legitimate authority like a King or Bishop, and was used to defend Christianity. Pope Alexander II developed recruitment systems via religious oaths from 1065 onwards. These became the basis of the recruitment system for the crusades.

    The First Crusade, 1096-99

    Despite the fact that the crusaders had all the odds against them, the First Crusade was very successful. It achieved many of the objectives that the crusaders had set.

    The Crusades Peter the Hermit StudySmarterMiniature of Peter the Hermit leading the People's Crusade (Egerton 1500, Avignon, fourteenth century), Wikimedia Commons.

    The People’s March

    Pope Urban planned to start the Crusade on 15 August 1096, the Feast of the Assumption, but an unexpected army of peasants and petty nobles set off before the Pope’s army of aristocrats under the leadership of a charismatic priest, Peter the Hermit. Peter was not an official preacher sanctioned by the Pope, but he inspired fanatical enthusiasm for the Crusade.

    Their march was punctuated by a lot of violence and quarreling in the countries they crossed, especially Hungary, despite the fact they were on Christian territory. They wanted to force the Jews they encountered to convert but this was never encouraged by the Christian church. They killed the Jews who refused. The crusaders pillaged the countryside killed those who stood in their way. Once they reached Asia Minor, most were killed by the more experienced Turkish army, for example at the Battle of Civetot in October 1096.

    The siege of Nicaea

    There were four main Crusader armies that marched towards Jerusalem in 1096; they numbered 70,000-80,000. In 1097, they reached Asia Minor and were joined by Peter the Hermit and the remainder of his army. Emperor Alexios also sent two of his generals, Manuel Boutiumites and Tatikios to assist in the fight. Their first objective was to retake Nicaea, which used to be part of the Byzantine Empire before it was captured by the Seljuk Sultanate of Rum under Kilij Arslan.

    Arslan was campaigning in Central Anatolia against the Danishmends at the time and initially did not think the Crusaders would pose a risk. However, Nicaea was subjected to a lengthy siege and a surprisingly large number of crusader forces. Upon realising this, Arslan rushed back and attacked the crusaders on 16 May 1097. There were heavy losses on both sides.

    The crusaders had trouble forcing Nicaea to surrender because they could not successfully blockade lake Iznik on which the city was situated and from which it could be supplied. Eventually, Alexios sent ships for the crusaders rolled on logs to be transported on land and into the lake. This finally broke the city, which surrendered on 18 June.

    The siege of Antioch

    The Siege of Antioch had two phases, in 1097 and 1098. The first siege was staged by the crusaders and lasted from 20 October 1097 to 3 June 1098. The city lay in a strategic position on the crusaders’ way to Jerusalem through Syria as supplies and military reinforcements were controlled through the city. However, Antioch was an obstacle. Its walls were over 300m high and were studded by 400 towers. The Seljuk governor of the city had anticipated the siege and had started stockpiling food.

    The crusaders raided the surrounding areas for food supplies in the weeks of the siege. As a result, they soon had to look further afield for supplies, putting themselves in a position to be ambushed. By 1098 1 in 7 crusaders was dying of starvation, which led to desertions.

    On 31 December the ruler of Damascus, Duqaq, sent a relief force in support of Antioch, but the crusaders defeated them. A second relief force arrived on 9 February 1098 under the Emir of Aleppo, Ridwan. They were also defeated and the city was captured on 3 June.

    Kerbogha, the ruler of the Iraqi city of Mosul, began a second siege of the city to drive the crusaders away. This lasted from 7 to 28 June 1098. The siege ended when the crusaders left the city to face Kerbogha’s army and succeeded in defeating them.

    The siege of Jerusalem

    Jerusalem was surrounded by arid countryside with little food or water. The crusaders could not hope to take the city through a lengthy siege and thus chose to assault it directly. By the time they reached Jerusalem, only 12,000 men and 1500 cavalry remained.

    Morale was low due to a lack of food and the harsh conditions the fighters had to endure. The different crusader factions were becoming increasingly divided. The first assault took place on 13 June 1099. It was not joined by all factions and was unsuccessful. The leaders of the factions had a meeting after the first attack and agreed that a more concerted effort was needed. On 17 June, a group of Genoese mariners provided the crusaders with engineers and supplies, which boosted morale. Another crucial aspect was a vision reported by the priest, Peter Desiderius. He instructed the crusaders to fast and march barefoot around the city walls.

    On 13 July the crusaders finally managed to organise a strong enough assault and enter the city. A bloody massacre ensued in which the crusaders indiscriminately killed all Muslims and many Jews.


    As a result of the First Crusade, four Crusader States were created. These were the Kingdom of Jerusalem, the County of Edessa, the Principality of Antioch, and the County of Tripoli. The states covered much of what is now called Israel and the Palestinian Territories, as well as Syria and parts of Turkey and Lebanon.

    The Second Crusade, 1147-50

    The Second Crusade took place in response to the fall of the County of Edessa in 1144 by Zengi, ruler of Mosul. The state had been established during the First Crusade. Edessa was the most northerly of the four crusader states and the weakest, as it was the least populated. As a result, it was frequently attacked by the surrounding Seljuk Turks.

    Royal involvement

    In response to the fall of Edessa, Pope Eugene III issued a bull Quantum Praedecessores on 1 December 1145, calling for a second crusade. Initially, the response was poor and the bull had to be reissued on 1 March 1146. Enthusiasm increased when it became apparent that King Louis VII of France and King Conrad III of Germany would lead the second crusade.

    Saint Bernard of Clairvaux

    Another major factor in establishing support for the Second Crusade was the contribution of French Abbot Bernard of Clairvaux. The Pope commissioned him to preach about the Crusade and he gave a sermon before a council was organised in Vezelay in 1146. King Louis VII and his wife Eleanor of Aquitaine presented themselves prostrate at the feet of the abbot to receive the pilgrim’s cross.

    Bernard later crossed into Germany to preach about the crusade. Miracles were reported as he travelled, which further increased enthusiasm for the crusade. King Conrad III received the cross from the hand of Bernard, while Pope Eugene travelled to France to encourage the enterprise.

    The Wendish Crusade

    The call for a second Crusade was met positively by southern Germans, but northern German Saxons were reluctant. They wanted to fight against the pagan Slavs instead, a preference expressed at an Imperial Diet in Frankfurt on 13 March 1157. In response, Pope Eugene issued the bull Divina dispensation on 13 April which said that there would be no difference in spiritual awards between the different crusades.

    The crusade failed to convert most of the Wends. Some token conversions were achieved, mainly in Dobion, but the pagan Slavs quickly turned back to their old ways once the crusading armies had left.

    By the end of the crusade, the Slavic lands had been ravaged and depopulated, especially the countryside of Mecklenburg and Pomerania. This would help future Christian victories since the Slavic inhabitants had lost power and livelihoods.

    The siege of Damascus

    After the crusaders reached Jerusalem, a council was convened on 24 June 1148. It was known as the Council of Palmarea. In a fatal miscalculation, the leaders of the crusade decided to attack Damascus instead of Edessa. Damascus was the strongest Muslim city at the time, and they were hoping that by capturing it they would gain the upper ground against the Seljuk Turks.

    In July, the crusaders gathered at Tiberias and marched towards Damascus. They numbered 50,000. They decided to attack from the West where orchards would provide them with a supply of food. They arrived at Darayya on 23 July but were attacked the following day. The defenders of Damascus had asked for help from Saif ad-Din I of Mosul and Nur ad-Din of Aleppo, and he had personally led an attack against the crusaders.

    The crusaders were pushed back away from the walls of Damascus which left them vulnerable to ambush and guerrilla attacks. Morale was dealt a severe blow and many crusaders refused to continue with the siege. This forced the leaders to retreat to Jerusalem.


    Each of the Christian forces felt betrayed. A rumour had spread that the Seljuq Turks had bribed the crusader leader to move to less defensible positions and that bred distrust amongst the crusader factions.

    King Conrad tried to attack Ascalon but no further help arrived and he was forced to retreat to Constantinople. King Louis remained in Jerusalem until 1149. Bernard of Clairvaux was humiliated by the defeat and tried to argue that it was the sins of the crusaders along the way that led to the defeat, which he included in his Book of Consideration.

    Relations between the French and the Byzantine Empire were badly damaged. King Louis openly accused Byzantine Emperor Manuel I of colluding with the Turks and encouraging attacks against the crusaders.

    The Third Crusade, 1189-92

    After the failure of the Second Crusade, Saladin, Sultan of both Syria and Egypt, captured Jerusalem in 1187 (at the Battle of Hattin) and reduced the territories of the crusader states. In 1187, Pope Gregory VIII called for another crusade to recapture Jerusalem.

    This crusade was led by three major European monarchs: Frederick I Barbarossa, King of Germany and Holy Roman Emperor, Philip II of France and Richard I Lionheart of England. Because of the three kings leading the Third Crusade, it is otherwise known as the Kings’ Crusade.

    The siege of Acre

    The city of Acre had already been under Siege by French nobleman Guy of Lusignan, however, Guy could not take the city. When the crusaders arrived, under Richard I, this was a welcome relief.

    Catapults were used in a heavy bombardment but the crusaders only managed to take the city after sappers had been offered cash to weaken the fortifications of the walls of Acre. The reputation of Richard the Lionhearted also helped secure victory as he was known as one of the best generals of his generation. The city was captured on 12 July 1191 and with it 70 ships, which made up the majority of Saladin’s navy.

    The Battle of Arsuf

    On 7 September 1191, Richard’s army clashed with Saladin’s army on the plains of Arsuf. Although this was meant to be the Kings’ Crusade, at this point only Richard Lionheart was left to fight. This was because Philip had to return to France to defend his throne and Frederick had recently drowned on his way to Jerusalem. The division and disintegration of leadership would become a key factor in the failure of the crusade, as the crusaders were aligned to different leaders and Richard Lionheart could not unite them all.

    The remaining crusaders, under Richard, carefully followed the coast so that only one flank of their army was exposed to Saladin, who mainly used archers and lance-bearers. Eventually, the crusaders unleashed their cavalry and managed to defeat Saladin’s army.

    The crusaders then marched on to Jaffa to reorganise. Richard wanted to take Egypt first to cut off Saladin’s logistical base but popular demand favoured marching directly towards Jerusalem, the original goal of the crusade.

    March to Jerusalem: the battle never fought

    Richard had taken his army within reach of Jerusalem but he knew that he could not stave off a counterattack by Saladin. His army had been significantly reduced in the last two years of continuous fighting.

    Meanwhile, Saladin attacked Jaffa, which had been captured by the Crusaders in July 1192. Richard marched back and managed to retake the city but to little effect. The crusaders had still not taken Jerusalem and Saladin’s army remained essentially intact.

    By October 1192, Richard had to return to England to defend his throne and hastily negotiated a peace deal with Saladin. The crusaders kept a tiny strip of land around Acre and Saladin agreed to protect Christian pilgrims to the land.

    The Fourth Crusade, 1202-04

    A Fourth Crusade was called by Pope Innocent III to recapture Jerusalem. The Prize was remission of sins, including if one financed a soldier to go in their place. The Kings of Europe were mostly preoccupied with internal issues and in-fighting and so were unwilling to engage in another crusade. Instead, Marquis Boniface of Montferrat was chosen, an eminent Italian aristocrat. He also had connections with the Byzantine Empire since one of his brothers had married the daughter of Emperor Manuel I.

    Financial issues

    In October 1202 the crusaders set sail from Venice for Egypt, known as the soft underbelly of the Muslim world, especially since Saladin’s death. The Venetians, however, demanded that their 240 ships be paid for, asking 85,000 silver marks (this was double the annual income of France at the time).

    The crusaders were unable to pay such a price. Instead, they made a deal to attack the city of Zara on behalf of the Venetians, which had defected to Hungary. The Venetians also offered fifty warships at their own cost in exchange for half of all territory conquered in the crusade.

    Upon hearing of the sack of Zara, a Christian city, the Pope excommunicated both the Venetians and the crusaders. But he quickly retracted his ex-communication because he needed them to carry out the crusade.

    Constantinople targeted

    The distrust between the Christians of the West and the East played a crucial role in the targeting of Constantinople by the crusaders; their objective had been Jerusalem from the start. Doge Enrico Dandolo, leader of Venice, was especially bitter at his expulsion from Constantinople whilst acting as the Venetian ambassador. He was determined to secure Venetian domination of trade in the east. He made a secret deal with Alexios IV Angelos, son of Isaac II Angelos, which had been deposed in 1195.

    Alexios was a western sympathiser. It was thought that getting him on the throne would give the Venetians a headstart in trade against their rivals Genoa and Pisa. In addition, some of the crusaders favoured the opportunity to secure Papal supremacy over the eastern church whilst others simply wanted Constantinople’s wealth. They would then be able to seize Jerusalem with financial resources.

    The sack of Constantinople

    The crusaders arrived in Constantinople on 24 June 1203 with a force of 30,000 Venetians, 14,000 infantrymen, and 4500 knights. They attacked the Byzantine garrison at nearby Galata. Emperor Alexios III Angelos was caught completely off guard by the attack and fled the city.

    The Crusades The Fall of Constantinople StudySmarterPainting of the Fall of Constantinople by Johann Ludwig Gottfried, Wikimedia Commons.

    The crusaders attempted to put Alexios IV on the throne along with his father Isaac II. Nonetheless, it quickly became clear that their promises were false; it turned out that they were very unpopular with the people of Constantinople. Having secured the support of the people and the army, Alexios V Doukas usurped the throne and executed both Alexios IV and Isaac II in January 1204. Alexios V promised to defend the city. However, the crusaders managed to overwhelm the city walls. Slaughter of the defenders of the city and its 400,000 inhabitants followed, along with the plunder of Constantinople and the rape of its women.


    The Partitio Romaniae treaty, which had been decided before the attack on Constantinople, carved up the Byzantine Empire among Venice and its allies. The Venetians took three-eighths of Constantinople, the Ionian Islands, and a number of other Greek islands in the Aegean, securing control of trade in the Mediterranean. Boniface took Thessalonica and formed a new Kingdom, which included Thrace and Athens. On 9 May 1204, Count Baldwin of Flanders was crowned the first Latin Emperor of Constantinople.

    The Byzantine Empire would be reestablished in 1261, a shadow of its former self, under Emperor Michael VIII.

    The Crusades - Key takeaways

    • The Crusades were a series of religiously motivated military campaigns that aimed to recapture Jerusalem.

    • The First Crusade was a result of Byzantine Emperor Alexios Comnenos I asking the Catholic Church to help him retake Jerusalem and prevent the territorial expansion of the Seljuk Dynasty.

    • The First Crusade was a success and led to the creation of four crusader kingdoms.

    • The Second Crusade was an attempt to recapture Edessa.

    • The Third Crusade, also known as the Kings’ crusade, was an attempt to recapture Jerusalem after the failure of the second crusade.

    • The Fourth Crusade was the most cynical. Initially, the motive was to recapture Jerusalem but the crusaders attacked Christian lands, including Constantinople.

    Frequently Asked Questions about The Crusades

    Q1. What were the Crusades?

    The Crusades were religiously motivated wars organised by the Latin Church to retake the Holy Land of Jerusalem.

    Q2. When was the First Crusade?

    The First Crusades began in 1096 and ended in 1099.

    Q3. Who won the Crusades?

    The First Crusade was won by the crusaders. The other three were failures and the Seljuk Turks kept Jerusalem.

    Where did the Crusades take place?

    The Crusades took place around the Middle East and Constantinople. Some notable locations were Antioch, Tripoli and Damascus.

    How many people died in the Crusades?

    From 1096–1291, the estimates of the dead range from one million to nine million.

    Test your knowledge with multiple choice flashcards

    How many silver marks did the Kingdom of Venice demand form the Crusaders for their ship provisions?

    Constantinople's trading docks thrived due to its natural harbour.

    Constantinople's natural harbour was formed due to its geographical location in-between Asia and Europe.


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