Answer:
Crusades were a series of campaigns, approved and promoted by the Catholic Church, that took place from the 11th to the 13th century. These were most aimed to secure Christian control over the Holy Land, which was under Muslim control at the time.
The crusades themselves did not limit Muslim expansion into Europe: in fact, it was not until the 1400s that they were completely expelled from Spain. However, the crusades were able to delimit the territories in which each religion predominated: although the crusaders did not recover the Levant for Christianity, they allowed Western Europe to become a bastion of their religion.