What role did Constantinople play in the crusades?

Constantinople served as a vital gateway for the Crusades, acting as the primary entry point for Western European armies into the Holy Land. The city was not only a strategic military hub but also a cultural and religious center, influencing the motivations and logistics of the Crusaders. Its capture during the Fourth Crusade in 1204, however, led to a significant shift in focus, as the Crusaders turned their attention to looting the city rather than advancing towards Jerusalem. This event marked a turning point, deepening the rift between the Eastern and Western Christian churches.