Editing Fourth Crusade (section)

=== War against Alexios V ===
[[File:Frammenti di mosaico pavimentale del 1213, 09.JPG|thumb|upright=1.2|Venetian mosaic from 1213 depicting the fall of Constantinople]]

The crusaders and Venetians, incensed at the murder of their supposed patron, demanded that Mourtzouphlos honour the contract that Alexios IV had promised. When the emperor refused, the Crusaders assaulted the city once again. On 8 April Alexios V's army put up a strong resistance, which did much to discourage the Crusaders. The Byzantines hurled large projectiles onto the enemy siege engines, shattering many of them. Bad weather conditions were a serious hindrance to the crusaders. A fierce wind blew from the shore and prevented most of the ships from drawing close enough to the walls to launch an assault. Only five of the wall's towers were actually engaged and none of these could be secured; by mid-afternoon it was evident that the attack had failed.{{sfn|Phillips|2004|pp=221–257}}

The Latin clergy discussed the situation amongst themselves and settled upon the message they wished to spread through the demoralised army. They had to convince the men that the events of 9 April were not God's judgment on a sinful enterprise: the campaign, they argued, was righteous and with proper belief it would succeed. The concept of God testing the determination of the crusaders through temporary setbacks was a familiar means for the clergy to explain failure in the course of a campaign. The clergy's message was designed to reassure and encourage the Crusaders. Their argument that the attack on Constantinople was spiritual revolved around two themes. First, the Greeks were traitors and murderers since they had killed their rightful lord, Alexios IV. The churchmen used inflammatory language and claimed that "the Greeks were worse than the Jews",{{sfn|Phillips|2004|pp=221–257}} and they invoked the authority of God and the pope to take action.

Although Innocent III had again demanded that they not attack, the papal letter was suppressed by the clergy, and the crusaders prepared for their own attack, while the Venetians attacked from the sea. Alexios V's army stayed in the city to fight, but when the unpaid Varangians left the city, Alexios V himself fled during the night. An attempt was made to find a further replacement emperor from amongst the Byzantine Greek nobility, but the situation had now become too chaotic for either of the two candidates who came forward to find sufficient support.{{citation needed|date=April 2021}}

On 12 April 1204, the weather conditions finally favoured the crusaders. A strong northern wind aided the Venetian ships in coming close to the walls, and after a short battle approximately seventy crusaders managed to enter the city. Some were able to knock holes in the walls, large enough for only a few knights at a time to crawl through; the Venetians were also successful at scaling the walls from the sea, though there was fighting with the Byzantine infantry. The remaining Anglo-Saxon "axe bearers" had been amongst the most effective of the city's defenders, but they now attempted to negotiate higher wages from their Byzantine employers, before dispersing or surrendering.{{sfn|Nicolle|2011|p=77}} The crusaders captured the [[Blachernae]] section of the city in the northwest and used it as a base to attack the rest of the city. While attempting to defend themselves with a wall of fire, however, they burned even more of the city. This second fire left 15,000 people homeless.{{sfn|Phillips|2004|p=209}} The crusaders completely took the city on 13 April.