rom the historical context and the various primary sources, it was easy to see that the largest issue that the
Crusaders had during the Fourth Crusade was funds and provisions. The Crusaders had owed huge sums of
money to the Venetians, even after they contributed everything that they had. Although the doge agreed to proceed to Egypt, it would have been impossible for the majority of the knights to survive with what little they had left -- many knights, out of sheer desperation, had to sell their horses in order to support themselves. Therefore, it is understandable that Alexius V's refusal to pay the Crusaders may have driven them over the edge.
CONCLUSION
A SIMPLE EXPLANATION
F
It is also worth noting that many Crusaders were motivated by both religious and personal agendas. As demonstrated in previous Crusades, many Crusaders had looted and robbed villages on their way to Jerusalem, getting rich off of the spoils of war. Some of them must have realized Constantinople was a much richer prize than all the Holy Land, and with its recent political instability, it would be much easier to raid.
CRUSADERS LOOTING AND KILLING IN CONSTANTINOPLE.
Thus, a combination of destitution and greed, amplified by rage induced by the actions of Alexius V, may have been the main cause of the sacking of Constantinople in 1204. Simple gluttony had driven the Crusaders to accomplish what the Turks failed to accomplish for over 500 years -- it was the first time that the Byzantine capital had ever been captured.