Fourth Crusade

European history

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July 23, 2026

Quick Summary

The Fourth Crusade, initiated by Pope Innocent III, was intended to recapture Jerusalem but was diverted to Constantinople. After agreeing to transport the Crusaders, Venice demanded payment, leading the Crusaders to first attack and capture the Christian city of Zara.12

Later, an exiled Byzantine prince offered the Crusaders a large sum and support for their mission if they helped him regain the throne in Constantinople. Despite papal disapproval, the Crusaders agreed and successfully installed the prince as emperor. However, when he failed to fulfill his promises, the Crusaders attacked and sacked Constantinople in April 1204. This event is widely seen as a betrayal driven by greed, which significantly weakened the Byzantine Empire and fractured Christian efforts against Muslims. Baldwin of Flanders was installed as emperor, but the empire fragmented, never fully recovering its former power.12

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Crusades
The Fourth Crusade and the Latin empire of Constantinople
Pope Innocent III was the first pope since Urban II to be both eager and able to make the Crusade a major papal concern. In 1198 he called a new Crusade through legates and encyclical letters. In…
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Pope Innocent III was the first pope since Urban II to be both eager and able to make the Crusade a major papal concern. In 1198 he called a new Crusade through legates and encyclical letters. In…
Read More

Sack of Constantinople
The diversion of the Fourth Crusade from the Holy Land to attack, capture, and pillage the Byzantine city of Constantinople in April 1204 divided and dissipated the efforts of the Christians to maintain the war against the Muslims. It is widely regarded as a shocking betrayal of principles out…
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The diversion of the Fourth Crusade from the Holy Land to attack, capture, and pillage the Byzantine city of Constantinople in April 1204 divided and dissipated the efforts of the Christians to maintain the war against the Muslims. It is widely regarded as a shocking betrayal of principles out…
Read More

Treaty of Venice
…negotiated between crusaders in the Fourth Crusade and Enrico Dandolo of Venice to provide transport at the cost of 85,000 marks. The crusaders’ failure to fulfill their monetary obligation was a major factor in the diversion of the crusade to Zara and Constantinople.
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…negotiated between crusaders in the Fourth Crusade and Enrico Dandolo of Venice to provide transport at the cost of 85,000 marks. The crusaders’ failure to fulfill their monetary obligation was a major factor in the diversion of the crusade to Zara and Constantinople.
Read More