The marvels of nature and the genius of medieval Arab military architecture have given northern Jordan two of the most important ecological and historical attractions in the Middle East: the sprawling pine forests of the Ajlun-Dibbine area, and the towering Ayyubid castle at Ajlun, which helped to defeat the Crusaders eight centuries ago. Ajlun Castle (Qal'at Ar-Rabad) was built by one of Saladin's generals in 1184 AD to control the iron mines of Ajlun, and to deter the Franks from invading Ajlun. Ajlun Castle dominated the three main routes leading to the Jordan Valley and protected the trade and commercial routes between Jordan and Syria; it became an important link in the defensive chain against the Crusaders, who, unsuccessfully spent decades trying to capture the castle and the nearby village. he original castle had four towers, arrow slits incorporated into the thick walls, and was surrounded by a moat averaging 16m in width and up to 15m deep. In 1215 AD, the Mameluk officer Aibak ibn Abdullah expanded the castle following Usama's death, by adding a new tower in the southeast corner and a bridge that can still be seen decorated with pigeon reliefs.