The Sack of Constantinople (1204)
The Sack of Constantinople, which took place from 12 to 15 April 1204, was one of the most notorious events of the medieval period. The eye-witness account by the French knight Geoffrey of Villehardouin, who marched with the Fourth Crusade and was one of the leaders of the diversion, remains the most important contemporary source. The army of the Fourth Crusade, diverted from its original purpose of recapturing Jerusalem, captured Constantinople, the capital of the Byzantine Empire and the largest Christian city in the world. For three days, the city was subjected to a systematic pillage. Churches were looted, libraries were destroyed, the population was killed, raped, or sold into slavery. The sack weakened the Byzantine Empire fatally, established the Latin Empire of Constantinople, and split the Greek and Latin churches in a way that would last for centuries. Jonathan Phillips’s The Fourth Crusade and the Sack of Constantinople (2004) is the standard modern treatment, and it is what I have leaned on for this cluster.
For the broader story, see the main article on the Fourth Crusade, the Latin Empire of Constantinople, and why the Fourth Crusade sacked Constantinople.
The City of Constantinople
Constantinople in 1204 was the largest and most populous city in Christendom, with perhaps 500,000 inhabitants. Founded by the Roman Emperor Constantine in 330 AD on the site of the Greek city of Byzantium, the city had been the capital of the Eastern Roman Empire for nearly nine centuries. It was a major center of trade, a hub of Christian learning, and the seat of the Ecumenical Patriarch, the head of the Greek Orthodox Church.
The city’s defenses were formidable. The Theodosian Walls, built in the 5th century, had protected the city against numerous sieges, including the sieges by the Avars and Persians in 626 and the siege by the Arab Umayyads in 717-718. The city was also protected by the Golden Horn, a natural harbor that could be closed by a great chain, and by the sea walls along the Marmara.
The city’s treasures were vast. The Great Palace of the Emperors, the Hippodrome, the great church of Hagia Sophia, the libraries and monasteries all contained enormous wealth. The relics of saints and the works of ancient Greek literature were preserved in the city’s churches and libraries. The sack of 1204 would distribute much of this wealth across Western Europe.
The First Siege (1203)
The army of the Fourth Crusade first arrived before Constantinople in July 1203. The Crusaders and Venetians, led by Enrico Dandolo, launched a coordinated assault on the city. The Venetians, with their formidable fleet, attacked the sea walls along the Golden Horn. The Crusader infantry attacked the land walls. The city was defended by a substantial garrison, but the walls were eventually breached at several points.
The assault was a success. The Greek population panicked, and the emperor Alexios III fled. Isaac II Angelos, who had been deposed and blinded by Alexios III, was restored to the throne. His son, Alexios IV, who had been the cause of the diversion of the Crusade, was now co-emperor. The new regime was supposed to pay the Crusaders the money promised in the agreement, and to support their expedition to Egypt.
The Failure of the Union
The new regime was unable to fulfill its promises. The Greek population was deeply hostile to the idea of union with Rome, and the new regime was unable to enforce the agreement. The Crusaders and Venetians, who had been promised money and supplies, grew increasingly frustrated. The relationship between the Latin and Greek populations deteriorated rapidly, and the city was on the verge of chaos.
In January 1204, a palace coup overthrew the regime of Isaac and Alexios IV. The new emperor, Alexios V Doukas Murzuphlos, took power and refused to honor the agreement with the Crusaders. The Crusaders were now without a pretext for their presence, and they were still deeply in debt to Venice.
The Second Siege (1204)
The leadership of the expedition, especially the Venetians, decided to take the city by force. A formal agreement was drawn up in March 1204, dividing the expected spoils of the city between the Crusaders and the Venetians. The terms were generous to the Venetians, who were to receive 3/8 of the city and the Greek Empire, while the Crusaders would receive 5/8.
The second siege of Constantinople began on 9 April 1204. The assault was launched from both land and sea. The Venetians, with their fleet, attacked the sea walls along the Golden Horn, while the Crusader infantry attacked the land walls. The defenses of the city were strong, but the Crusaders were determined and well-led. After a hard-fought assault, the walls were breached on 12 April 1204.
The Three Days of the Sack
The Crusaders and Venetians poured into the city on 12 April 1204. For three days, Constantinople was subjected to a systematic pillage. Churches were looted, monasteries were stripped, palaces were sacked. The famous library of Constantinople was destroyed. The relics of saints were seized, including the Crown of Thorns and other sacred objects that would later be venerated in Western Europe.
The population of the city was killed, raped, or sold into slavery. The famous bronze horses of the Hippodrome, attributed to the sculptor Lysippos, were taken to Venice, where they still stand above the entrance to St. Mark’s Basilica. The damage to the city’s infrastructure was so severe that Constantinople would never fully recover.
The sack of Constantinople shocked the medieval world. Pope Innocent III condemned the sack, but he was unable to prevent it. The papacy had been a driving force behind the Fourth Crusade, and the failure of the expedition to achieve its central objective was a major embarrassment. The legacy of 1204 would shape the relationship between the Latin and Greek churches for centuries.
The Establishment of the Latin Empire
The sack of Constantinople was followed by the establishment of the Latin Empire of Constantinople. Baldwin of Flanders, one of the leaders of the Fourth Crusade, was crowned the first Latin Emperor of Constantinople in May 1204. The empire was formally established on the basis of a partition agreement signed between the Crusaders and the Venetians.
The Latin Empire would survive for 57 years, until the Byzantines recaptured Constantinople in 1261. The empire was always fragile, dependent on the support of Western Europe and threatened by the resurgent Greek states in the East. The empire’s fall in 1261 was a major blow to the Latin Church, and it would set the stage for the eventual Ottoman conquest of the city in 1453.
The Long-Term Consequences
The sack of Constantinople was a major turning point in the history of the medieval world. The Byzantine Empire, although it would survive in exile for another 57 years, was fatally weakened. The Greek Orthodox Church was split from Rome in a way that would last until modern times. The cultural treasures of Byzantium were dispersed across Europe, and the Latin West gained access to the wealth of Greek learning that would eventually fuel the Renaissance.
The sack of Constantinople also had a major impact on the Crusades. The diversion of the Fourth Crusade was a profound moral failure, and it showed that the papacy’s control of the Crusading movement was limited. The Fifth Crusade and subsequent expeditions would be conducted with greater care, but the memory of 1204 would linger. The Latin Empire, meanwhile, would divert Western resources from the defense of the Latin East, making the Crusader States more vulnerable to Muslim pressure.
The sack of Constantinople has been the subject of intense modern scholarship. The most important modern work is Jonathan Phillips’s The Fourth Crusade and the Sack of Constantinople (2004), which provides a detailed and balanced account of the expedition. Phillips argues that the diversion of the Crusade was not a simple case of Venetian greed, but a complex story of debt, political calculation, and personal ambition. Other important works include those by Steven Runciman, Donald Queller, and Thomas Madden.
The sack is also significant for its impact on European culture. The transmission of Greek texts to the West, including the works of Aristotle, Plato, and many others, was a major factor in the development of Scholasticism and eventually of the Renaissance. The Fourth Crusade, in this sense, had effects that extended far beyond the immediate political and military events of 1204.