Siege of Constantinople (1203)

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Siege of Constantinople
Part of the Fourth Crusade
Map of Constantinople during the Byzantine era
Date 11 July – 1 August 1203 Location Constantinople, Byzantine Empire (modern-day Istanbul, Turkey) Result Crusaders victory Alexios IV Angelos takes Byzantine throne
Belligerents
Fourth Crusade loyalist of Alexios IV Angelos	Byzantine Empire
Commanders and leaders
Boniface I Enrico Dandolo	Alexios III Angelos
Strength
Crusaders: 10,000 men[1] Venetians: 10,000 men[1] and 210 ships[2]	15,000 men[3] and 20 ships[4]

The siege of Constantinople in 1203 was a crucial episode of the Fourth Crusade, marking the beginning of a series of events that would ultimately lead to the fall of the Byzantine capital. The crusaders, diverted from their original mission to reclaim Jerusalem, found themselves in Constantinople, in support of the deposed emperor Isaac II Angelos and his son Alexios IV Angelos. The besieging forces, primarily composed of Western European knights faced initial setbacks, but their determination and advanced siege weaponry played a pivotal role in pressuring the Byzantine defenders.

Amidst the chaos, the Byzantine emperor was overthrown, leading to a power vacuum and setting the stage for the more infamous events of 1204 when the crusaders, frustrated by unpaid debts and political turmoil, eventually sacked the city. This marked the first time in nearly nine centuries that Constantinople fell to an external force, forever altering the course of Byzantine history.