What were the Crusades fighting over?

Answer 1

The justification for the Crusades began in 1009 when the Fatimid Caliph of Cairo had the Church of the Holy Sepulchre in Jerusalem destroyed. His successor permitted the Byzantine Empire to rebuild it under stringent circumstances, and pilgrimage was again permitted, but many stories began to be circulated in the West about the cruelty of Muslims toward Christian pilgrims.

The Christians of the first Crusade captured Jerusalem and large areas of Palestine, but Jerusalem was soon lost. Successive Crusades were launched to recapture Jerusalem and drive the Muslims out of Palestine, but were largely unsuccessful.

In the thirteenth century, the Knights Hospitaller finally left for the island of Rhodes, abandoning the entire Near East to the Muslims.