Fourth Crusade
The Fourth Crusade set out in 1202 with a clear mandate from Pope Innocent III: retake Jerusalem from Muslim control by first striking at the heart of Ayyubid power in Egypt. It never reached Egypt. It never reached Jerusalem. Instead, the army that was supposed to defend Christendom ended up sacking the greatest Christian city in the world. How did a holy war against Islam become a catastrophic assault on the Byzantine capital of Constantinople? The answer runs through debt, ambition, personal vengeance, and a sequence of decisions that each seemed defensible in isolation but together produced a disaster that reshaped the medieval world. The crusade's final toll was not measured in Muslim casualties but in the partition of a thousand-year-old empire, the deepening of a religious schism that has never fully healed, and a weakening of Byzantium so severe that it hastened the empire's eventual fall to the Ottomans in 1453.
In 1187, the Ayyubid Sultan Saladin conquered most of the Crusader states in the Levant, reducing them to little more than three coastal cities: Tyre, Tripoli, and Antioch. Jerusalem was lost. The Third Crusade (1189-1193) was launched in direct response, and it achieved a partial recovery, retaking Acre and Jaffa and effectively reestablishing the Kingdom of Jerusalem, though the city of Jerusalem itself stayed in Ayyubid hands. The Treaty of Jaffa was signed with Saladin on the 2nd of September 1192, ending the fighting with a truce set to last three years and eight months.
The tensions left behind were not only religious. Emperor Frederick I Barbarossa had nearly besieged Constantinople during the Third Crusade after the Byzantine government failed to grant him safe passage across the Dardanelles. King Richard I of England seized the Eastern Roman province of Cyprus and handed it to Guy of Lusignan rather than returning it to the empire. These episodes seeded a mutual suspicion between western Crusaders and Byzantium that would prove consequential.
Saladin died on the 4th of March 1193, and his empire fractured among his heirs. By the time a new crusade was being organized, his brother al-Adil had reunified the empire, acquiring Egypt in 1200 and Aleppo in 1202, so that his domains almost completely surrounded what remained of the Crusader states. It was this reconsolidated Ayyubid power that the planners of the Fourth Crusade hoped to break.
Pope Innocent III succeeded to the papacy in January 1198, and a new crusade became the central ambition of his pontificate. His call found little traction among Europe's monarchs, but the preaching of Fulk of Neuilly reached the nobility. In November, Count Thibaut of Champagne hosted a tournament at his castle in Ecry-sur-Aisne, and during the festivities he vowed to dedicate his weapons to God's service. By early 1200, the leading crusader barons, including Thibaut, Louis of Blois, and Baldwin of Flanders, gathered at Soissons and agreed to sail to Egypt rather than march overland.
To arrange transport, the lords appointed a six-member committee that included Geoffrey of Villehardouin, who would later chronicle the crusade. They opened negotiations with the doge of Venice, Enrico Dandolo, in March 1201. Dandolo agreed to transport 33,500 crusaders, a figure that required a full year of Venetian preparation, including building numerous ships and training crews, all while curtailing the city's commercial activity. The contracted force was to include 4,500 knights and horses, 9,000 squires, and 20,000 foot-soldiers. The agreed price was 85,000 silver marks.
Thibaut, elected leader of the crusade, died suddenly in 1201 before the expedition could sail. His replacement was Boniface of Montferrat, brother of Conrad of Montferrat, who had died defending Tyre. The army was due to sail on the 24th of June 1203 and proceed directly to the Ayyubid capital, Cairo. The pope ratified this agreement and imposed a solemn ban on any attacks against Christian states.
By May 1202, the bulk of the crusader army had gathered at Venice, but the numbers fell far short of the contract. Many crusaders had sailed from other ports, particularly Flanders, Marseille, and Genoa. About 12,000 men arrived, roughly 4,000-5,000 knights and 8,000 foot-soldiers, rather than the planned 33,500. The Venetians had honored their side of the deal, assembling 50 war galleys and 450 transports, enough for three times the army that appeared. They refused to let the crusaders depart without full payment.
The crusaders could produce only 35,000 silver marks initially. A further 14,000 marks were squeezed out by reducing the crusaders to extreme poverty, still leaving the full sum unpaid. Dandolo, who had joined the crusade during a public ceremony in the church of San Marco, proposed a way out: the crusaders would delay payment by first helping Venice retake the port of Zara on the Adriatic coast. Zara had been a Venetian economic dependency but had rebelled in 1181 and placed itself under the protection of the Catholic King Emeric of Hungary. Emeric had himself taken the cross.
Many crusaders objected. Simon V de Montfort refused to participate and left the expedition. Pope Innocent III wrote threatening excommunication. His letter, delivered by Peter of Lucedio, may not have reached the army in time. The bulk of the army arrived at Zara on 10-the 11th of November 1202. The citizens hung banners marked with crosses from their windows and the walls to signal their Christian identity. The city fell on the 24th of November 1202 after a brief siege. When Innocent III heard of the sack, he excommunicated the entire crusader army, though in February 1203 he rescinded the excommunication against all non-Venetians, regarding them as having been coerced.
While the crusaders wintered in Zara, an offer arrived from the Byzantine prince Alexios Angelos, son of the deposed emperor Isaac II. His uncle, Alexios III Angelos, had seized the throne by palace coup in 1195, blinding Isaac as a traditional punishment. The young Alexios had fled to Philip of Swabia, who was Boniface of Montferrat's cousin. On the 1st of January 1203, the terms of a new agreement reached the crusade's leaders.
Alexios offered to pay the entire debt owed to the Venetians, give 200,000 silver marks to the crusaders, provide 10,000 Byzantine professional troops and maintain 500 knights in the Holy Land permanently, furnish the Byzantine navy to transport the crusaders onward to Egypt, and place the Eastern Orthodox Church under the authority of the Pope. All of this in exchange for military support to topple Alexios III and restore his father to the throne.
Doge Dandolo strongly backed the plan. The source notes, however, that given Dandolo's earlier experience as an ambassador to the Byzantine Empire, he likely knew that no Byzantine emperor could realistically raise such sums or deliver such promises. Most other crusade leaders, encouraged by bribes from Dandolo, eventually agreed. Dissidents led by Renaud of Montmirail sailed on to Syria rather than accept the diversion. The remaining fleet, including 60 war galleys, 100 horse transports, and 50 large transports, sailed in late April 1203, also carrying 300 siege engines.
Constantinople at the time of the Fourth Crusade had stood for 874 years and was the largest and most sophisticated city in Christendom. Its triple walls stretched 20 km, its population numbered roughly half a million people, and it preserved the civic structures, aqueducts, and forums of classical Rome in working condition. The city controlled trade routes linking the Mediterranean to the Black Sea, China, India, and Persia.
The crusaders reached Constantinople on the 23rd of June 1203. The city held a garrison of 15,000 men including 5,000 Varangian guards, and a fleet of 20 galleys. On the 6th of July, the largest ship in the crusaders' fleet, the Aquila (Eagle), broke the massive chain blocking the Golden Horn. The Crusaders took positions opposite the Palace of Blachernae on the 11th of July. On the 17th of July, during a joint assault by land and sea, the Venetians captured a section of wall covering about 25 towers, but a fire set to cover their retreat destroyed around 120 acres of the city and left some 20,000 people homeless.
Alexios III responded by leading 17 divisions from the St. Romanus Gate, outnumbering the crusaders considerably. His force of roughly 8,500 men faced about 3,500 crusaders and then simply returned inside without fighting. His nerve had broken. He fled to Mosynopolis in Thrace during the night. Imperial officials quickly restored the blinded Isaac II. On the 1st of August, Isaac's son was crowned co-emperor as Alexios IV Angelos. The crusaders had achieved their stated purpose, and in doing so lost all legal justification for remaining.
Alexios IV immediately confronted the impossibility of his promises. His predecessor, Alexios III, had fled with 1,000 pounds of gold and priceless jewels, emptying the treasury. The co-emperor ordered the destruction and melting of valuable Roman icons to extract their metal, and still could only raise 100,000 silver marks. The Byzantine historian Nicetas Choniates called this order "the turning point towards the decline of the Roman state". Popular resentment of the young emperor and his foreign backers grew rapidly.
In August 1203, rioting broke out during Alexios IV's absence. Crusaders and Venetians who entered the city in retaliation set a fire that burned from 19 to the 21st of August, leaving an estimated 100,000 people homeless. In January 1204, the incapacitated Isaac II died, probably of natural causes. A nobleman named Alexios Doukas, known as Mourtzouphlos, overthrew Alexios IV, imprisoned him, and had him strangled in early February. Doukas was then crowned Emperor Alexios V.
On the 12th of April 1204, a strong northern wind finally gave the Venetian fleet the angle it needed to reach the walls. About seventy crusaders entered the city; the remaining Anglo-Saxon defenders, described as "axe bearers", attempted to negotiate higher wages from their Byzantine employers before dispersing. Alexios V himself fled during the night. The crusaders captured the Blachernae section and used it as a base. The city was fully taken on the 13th of April 1204. The crusaders then sacked it for three days, stealing or ruining many ancient and medieval works of art, looting churches and monasteries, and killing members of the civilian population. The total amount looted was estimated at about 900,000 silver marks. The Venetians received 150,000 marks that were their due, while the crusaders received 50,000 marks; a further 100,000 were split evenly, and 500,000 were secretly kept by many crusader knights.
Pope Innocent III, upon learning what his crusade had done, was, in the words of the source, "filled with shame and rage". He had forbidden the attack and wrote angry letters to Boniface of Montferrat afterward. The poet Guilhem Figueira expressed the sentiment of many critics more bluntly, writing that Rome had its "seat in hell-fire and ruin" and that the papacy had massacred Greeks and Latins while doing little harm to the Saracens.
The Byzantine Empire was partitioned between Venice and the crusade's leaders according to a formal treaty establishing the Latin Empire of Constantinople. Boniface of Montferrat, despite being the campaign's commander, was passed over for emperor. The Venetians distrusted him because his brother Renier of Montferrat had been married to Maria Komnene, empress in the 1170s and 1180s. Baldwin of Flanders was placed on the throne instead. Boniface went on to found the Kingdom of Thessalonica as a vassal state.
Three Byzantine successor states emerged immediately: the Empire of Nicaea under Theodore Laskaris, the Empire of Trebizond, and the Despotate of Epirus. The Nicaean Empire eventually retook Constantinople in July 1261 with Genoese naval support. But the restored empire was territorially diminished, having lost control of most of the Balkans, Anatolia, and the Aegean islands. The treasury had been plundered, the population depleted, the defenses hollowed out. These were the conditions that left the empire unable to resist the expanding Ottomans in the following centuries. The Ottomans, under Sultan Mehmed II, took Constantinople in 1453, ending the Eastern Roman Empire that had endured for more than a millennium. Only a handful of the crusaders who had set out to liberate Jerusalem ever reached the Holy Land.
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Common questions
Why did the Fourth Crusade attack Constantinople instead of Egypt?
The Fourth Crusade attacked Constantinople due to a combination of financial debt and political opportunity. After the crusader army arrived at Venice in 1202 with far fewer men than contracted, they could not pay the 85,000 silver marks owed. Doge Enrico Dandolo proposed they offset the debt by attacking Zara, and later by backing the Byzantine prince Alexios IV Angelos, who promised 200,000 silver marks and military support if they placed him on the Byzantine throne.
Who called the Fourth Crusade and what was its original goal?
Pope Innocent III called the Fourth Crusade in January 1198. Its stated goal was to recapture Jerusalem from Muslim control by first defeating the Ayyubid Sultanate in Egypt, which was the dominant Muslim power in the eastern Mediterranean. The crusaders planned to sail directly to Cairo.
What was the sack of Constantinople in 1204?
The sack of Constantinople in 1204 was a three-day plundering of the Byzantine capital by crusader and Venetian forces. The city was looted of an estimated 900,000 silver marks in total. Ancient and medieval works of art were stolen or destroyed, churches and monasteries were looted, and civilians were killed. Eyewitness accounts were left by Niketas Choniates, Geoffrey of Villehardouin, Robert of Clari, and the anonymous author of the Devastatio Constantinopolitana.
What was the Frankokratia and how long did it last?
The Frankokratia was the period of Latin and Venetian rule over former Byzantine territories following the Fourth Crusade. It encompassed multiple states, including the Latin Empire of Constantinople, the Kingdom of Thessalonica, the Principality of Achaea, and the Duchy of Athens. The period lasted at different durations by region; most of these territories were absorbed by the Ottoman Empire between the 14th and 17th centuries, though some Venetian holdings persisted until the end of the Republic of Venice in 1797.
What long-term damage did the Fourth Crusade do to the Byzantine Empire?
The Fourth Crusade left the Byzantine Empire depleted of soldiers, resources, and money, with most of the Balkans, Anatolia, and the Aegean islands lost. Though the Nicaean Empire retook Constantinople in July 1261, the restored empire was territorially and financially weakened. These conditions made Byzantium vulnerable to the expanding Ottomans, who conquered Constantinople in 1453 under Sultan Mehmed II.
Who opposed the Fourth Crusade's diversion to attack Constantinople?
Several prominent crusaders refused to participate in the attacks on Zara and Constantinople, including Enguerrand II of Boves, Simon de Montfort, 5th Earl of Leicester, and Guy of Vaux-de-Cernay. Pope Innocent III had explicitly forbidden attacks on Christian states and excommunicated the crusader army after the fall of Zara. The French Byzantinist Jonathan Harris noted that many who remained in the army agreed to the diversion only very reluctantly, under financial and emotional pressure.
All sources
31 references cited across the entry
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- 30NewsPope sorrow over ConstantinopleJune 29, 2004
- 31NewsEcumenical Patriarch Bartholomew I — April 2004