Crusader fortifications were military structures built during the Crusades, a series of religious wars from the 11th to 13th centuries. These fortifications were designed to protect against attacks and to control key territories in the Holy Land. They often featured thick stone walls, towers, and moats, making them formidable against enemy forces. Many of these forts, such as Kerak and Acre, showcased advanced architectural techniques of the time. The use of arrow slits, drawbridges, and fortified gates allowed defenders to repel sieges effectively. These structures played a crucial role in the military strategies of the Crusaders and influenced later European fortification designs.