The Second Age of the Crusaders Episode 4 "The Sack of Constantinople"

The Fourth Crusade was initiated as a plan to attack Egypt. But with the Crusaders short of money, and the emergence of a Byzantine pretender, claiming that he would help the Crusaders if they helped him, things started to develop somewhat differently. With the scheming Venetians in the background, the Crusaders looked east not to the Holy Land but to the glittering city of Constantinople.