The well preserved castle of Ajloun was built between 1184 and 1188 by Izz ad Din Usama bin Munqidh, who was one of Saladin's generals and also his nephew.
The castle's location made it strategically important in the defense against the Crusaders. It was also a key link in communication chains between Syria and Egypt, using beacons and pigeon post. The building has been destroyed, rebuilt and occupied by a number of invaders and armies, including the Mongols, Mamluks and Ottomans. It was also badly damaged by earthquakes in 1837 and 1927, with restoration still continuing.