Why did the Seventh Crusade attack Egypt instead of Jerusalem?

Louis IX chose to attack Egypt during the Seventh Crusade as a strategic maneuver to break Muslim power in the region before attempting to reclaim Jerusalem. By seizing principal towns in Egypt, Louis intended to use them as hostages to be exchanged for Syrian cities, thereby securing the Holy Land.12

This strategy was not unique to Louis IX; it had been an accepted military approach among Crusade leaders since the Fifth Crusade, as it was believed that Egypt served as the primary source of Muslim strength in the Levant. By targeting Egypt, the Crusaders hoped to neutralize the sultan's military capacity, which they viewed as a prerequisite for the successful restoration of Western rule in Jerusalem.2