 By the early 13th century, the Al Fadl dominated the desert region between Homs in the west to the Euphrates valley in the east and from Qal'at Ja'bar southward through central Najd.Isa's great-grandfather, Haditha (grandson of the Al Fadl's progenitor, Fadl ibn Rabi'ah), served as the first "amir al-ʿarab" (commander of the Bedouin tribes) under Ayyubid sultan al-Adil (r. 1200–1218), beginning a tradition of Al Fadl tribesmen being appointed to the office.Isa's father Muhanna and grandfather Mani (d. 1232) both served the post.