 Izz al-Din Usama

Izz al-Din Usama was a 12th-century Ayyubid "emir" and a nephew of Saladin.In 1183, he was ordered by Saladin to build the Rabbadh Fortress at Ajlun in northern Jordan (known as "al-Urdunn" at the time) with the purpose of protecting Ayyubid holdings in area and threatening the Crusader forces based in Kerak to the south.