Known as Arrabadh castle. Muslims built the castle to keep an eye on the existence of the crusaders in the region. Izz Eddeen Osama, one of the cousins of Saladin, succeeded to build the castle in 1184 AD, choosing the most strategic location on top of Jabbal Ajloun, controlling the rift valley, and the eastern trade routes. Three years later, the Hitteen battle started to put an end to the existence of the crusaders in 1187 AD.