Fourth Crusade

In the fourth Crusade the Christian armies destroyed the Christian cities
of Constantinople and Zara. The Children's crusade of 1212 was a tragedy based on the mistaken belief that God would empower Christian children to overwhelm Muslim amies. Most died without ever reaching the Holy Land.
It all came to an end in1291 whenMuslims recaptured Acre, and slaughtered its garrison. The Holy Land was now back in Muslim hands. Two hundred years of death and destruction had been for nothing.