A crusader castle refers to the fortifications built by the European knights during the Crusades, a series of religious wars from the 11th to the 13th centuries. These castles were strategically located in the Holy Land to protect Christian territories and serve as military strongholds. They often featured thick stone walls, towers, and moats to defend against attacks. Many crusader castles, such as Krak des Chevaliers in Syria and Montfort Castle in Israel, showcase advanced medieval architecture. They were designed not only for defense but also to provide living quarters for knights and their families. Today, these castles are important historical sites that attract tourists and historians alike.