The Impact of the Fourth Crusade: The First Fall of Byzantium

During the Fourth Crusade, feudal lords under the leadership of the Venetian Republic laid siege to Constantinople, conquering the city, and creating the Latin Empire.

Dec 25, 2021By Igor Radulovic, MA History Education, BA Art History
sack of Constantinople crusader ships
Sack of Constantinople, by Palma Le Jeune, 16th or early 17th century, via War History Online; with Crusade of 1204, by Tintoretto, 16th Century, via


In the middle of the 11th century, the idea of the ​​Crusades first appeared in Europe. The original goal was the liberation of Jerusalem. In the First Crusade, knights managed to capture Jerusalem in 1099. The city remained in Christian hands until Saladin’s conquest in 1187, after which time the Third Crusade was organized. Unsuccessful attempts to restore rule over Jerusalem and the failure of the campaign led to the launch of the Fourth Crusade. This failed crusade would lead not to the reconquest of Jerusalem, but to the siege of Constantinople.


Preparation for the Fourth Crusade

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Relief Portrait of Innocent III, by Joseph Kiselewski, 1950, via the Capitol, Washington


Pope Innocent III, a dynamic, ambitious, and educated pope whose pontificate would mark the launch of the Fourth Crusade, ascended the throne of St. Peters in 1198. Unlike his predecessors, he did not have much help from other European rulers. After the death of Emperor Henry VI, the throne of the Holy Roman Empire remained vacant. Henry left behind his underage son Frederick II, who was soon embroiled in a conflict.


The situation was not much better in England, where after a period of captivity in Germany, King Richard the Lionheart returned home from the Third Crusade. Richard had problems with the French King Philip II, who had taken over his territories in Normandy, and consequently, he went to war with France.


From the moment he arrived as the head of the church, Innocent planned the Fourth Crusade to raise his profile. The Crusaders intended to attack Egypt, who controlled Jerusalem. Having no money or fleet, they turned to Venice for help.


The Situation in the Byzantine Empire 

komnenus empire map fourth crusade
Empire of the Comnenus dynasty in 1174, under Manuel I, by Neimwiki, via Wikimedia Commons

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Until the 11th century, the Byzantine Empire was a powerful state, a bulwark of Christianity against Islam. The Byzantines bravely defended themselves until a new threat arrived from the east with the invasions of the Seljuk Turks. Under the rule of the Comnеnus dynasty, the empire managed to halt its decline for some time. The policy of family rule proved successful during the reign of Emperor Alexius I and his son John II Comnenus. With the death of Manuel I, however, the problems of the Byzantine Empire resurfaced. Manuel was succeeded by his eleven-year-old son Alexius II, who was tragically assassinated by the last emperor of the Comnenus dynasty, Andronicus I. Andronicus in turn was killed by an angry street mob.


The new Angelus dynasty did nothing to prevent an unstoppable decline. The first ruler of this dynasty was Isaac II Angelus (1185-1195). The new ruler did not try to prevent abuses during the collection of taxes, nor did he prevent the sale of rank. Isaac’s first reign ended in a coup in which he was captured and blinded, while his older brother Alexius III (1195-1203) took power. The situation in the Byzantine Empire on the eve of the Fourth Crusade was catastrophic.


Gathering the Crusaders 

enrico dandelo fourth crusade
Doge Enrico Dandolo Recruiting for the Crusades, by Jean Leclerc, 1621, via the Web Gallery of Art


No European monarchs responded to the invitation of Pope Innocent III, but he received a response from some Frankish, Flemish, and Italian nobles. Boniface of Montferrat was appointed as the head of the Fourth Crusade, because he was one of the party’s most distinguished lords.


The Crusaders agreed to gather in Venice and the Venetians agreed they would transport the Crusaders to Egypt for 85,000 silver marks. The Venetian Doge Enrico Dandolo agreed to transport 30,000 soldiers and 4,500 horses to Egypt. It wasn’t long before the Crusaders began to realize that they didn’t have enough money to pay because a much smaller number of people arrived in Venice than was stipulated in the contract.


As a result, the cunning Venetian doge managed to redirect the goal of the Fourth Crusade. The Venetian Republic, which had recently established trade relations with Egypt, and did not wish to go to war there, but they suggested that the Crusaders take Zara, a Catholic city on the Dalmatian coast, as compensation for the Venetians.


The Fall of Zara and the Creation of a New Plan

tintoretto conquest of zara fourth crusade
Conquest of Zara, by Jacopo Tintoretto, 1580, via the Web Gallery of Art


When the Crusaders appeared in front of Zara, the population and the garrison let down flags covered with crosses in an effort to save themselves.  Nevertheless, the Crusaders occupied the city port and began the siege and Zara surrendered. The Venetians took over part of the city along the harbor, while the Crusaders took the rest.


In Zara, Alexius Angelus (later Alexius IV), the son of the overthrown Byzantine emperor Isaac II, addressed the soldiers and offered them money to help him regain his throne. Alexius promised to put the Byzantine church under Roman Catholic rule, to give the Crusaders 200,000 silver marks, and provide them with supplies for a year. He also promised 10,000 additional soldiers to conquer Egypt, and he agreed to finance 500 knights in the Holy Land.


Some of the Crusaders strongly opposed further deviations from the road and demanded that they move immediately towards Syria. The rest advocated for the conquest of Constantinople, which would provide them with funds and military support which would be of great help in the continuation of their campaign. Pope Innocent strongly opposed any action in Constantinople. He sent a letter, which arrived in Zara after the Crusaders had already accepted Alexius’ offer and set out for the Golden Horn.


The Siege of Constantinople

tintoretto siege of constantinople
Crusade of 1204, by Tintoretto, 16th Century, via


On June 24, 1203, the Crusaders landed in Chalcedon, a small town on the Asian shores of the Bosporus. There, there was an imperial castle in which the crusading lords met. The siege of Constantinople was on its way. Emperor Alexius III sent a detachment to expel the Crusaders from but the Crusaders defeated them. A day later, the mission of Emperor Alexius III arrived at the crusading camp. It became clear to everyone that the king did not intend to hand over power to his nephew. The Crusaders decided to take a risk and start the siege of Constantinople. The Byzantines, led by Theodore Lascaris, tried to defeat the Crusaders, without success.


The Crusaders launched a final fatal attack on July 17. That night, Alexius III left Constantinople, carrying with him all the treasures he could take, leaving behind his people and his family. Isaac Angelus was released from the dungeon and returned to the throne. After that, Isaac, at the request of the Crusaders, confirmed the contract his son had concluded with them. On August 1, Prince Alexius was officially crowned co-ruler under the name of Alexius IV Angelus. He introduced new levies, emptied the state coffers, and confiscated property, but only managed to collect half of the sum he had promised to the Crusaders.


The Conflict Between Alexius IV and the Crusaders

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The Entry of the Crusaders into Constantinople, by Eugène Delacroix, 1840, via


The new levies and the fire in Constantinople during the siege created a great anti-crusade mood. Conflicts between the Byzantines and the Crusaders broke out more and more often throughout the city. These clashes culminated when the Crusaders set a fire around the Church of St. Sophia.


The Crusaders waiting on the other side of the bay were waiting for the payment of their debt. As small amounts of money arrived, the Crusaders saw through Alexius’s intentions. Boniface of Montferrat went to Alexius IV demanding payment. But soon, on the recommendation of his advisors, Alexius stopped making any more payments. Angered by Alexius’ behavior, the Crusaders and the Venetians convened a meeting. The embassy went to the court and demanded the payment. Otherwise, they would take what belonged to them.


After these events, the influence and authority of the Angelus dynasty collapsed like a tower of cards. The development of the situation and the cowardly behavior of the ruler led to a coup d’état on January 25, 1204. Alexius V Ducas was proclaimed the new emperor and Alexius IV was killed in the dungeons. A few days later, his father Isaac also died. The Crusaders turned to the outskirts of Constantinople, looting and destroying everything in their path.


The Fourth Crusade and the Fall of the Byzantine Empire

remnants byzantine empire 1265
Map of the Remnants of the partially-restored Byzantine Empire in 1265, via Britannica


The capture of Constantinople on April 13, 1204, in the Fourth Crusade was one of the epochal events of medieval history. The siege of Constantinople and the looting and burning of the city only deepened the intolerance between the Eastern and Western Christians. It also influenced the creation of the states that emerged in the territory of the Byzantine Empire.


After the Fourth Crusade, the Western Christians formed several Latin states, the most important being the Latin Empire of Constantinople. Baldwin of Flanders had the honor of becoming the first emperor. Boniface of Montferrat decided to establish a state of his own, thus creating the Kingdom of Thessaloniki, a vassal state to the Latin emperor. The Principality of Achaea and the Duchy of Athens were also formed.


The Byzantines maintained control over parts of modern-day Albania and western Turkey, but parts of Albania and part of Greece also became the so-called Despotate of Epirus, while part of Asia Minor became the Empire of Nicaea. A small coastal area in the north of today’s Turkey, became the so-called Empire of Trebizond. In 1261, the emperor of Nicaea, Michael VIII Palaeologus, managed to recapture Constantinople, overthrowing the Latin Empire, and restoring parts of the Byzantine Empire. However, the renewed Byzantine Empire was only a shadow of its former power and wealth. The wounds inflicted during the Fourth Crusade would never heal.

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By Igor RadulovicMA History Education, BA Art HistoryIgor is a historian and a history teacher from Podgorica, Montenegro. His main focus are contemporary history and controversial historical topics. He still likes researching different periods, spanning from ancient to modern history.