Al-Adil therefore turned his army on the Zengid cities of Al-Khabur, which he took, and Nusaybin, which he trusted Al Mansur and Al-Ashraf to take, while he tried, unsuccessfully, to take Sinjar.
Arbayistan was a Sassanid Persian satrapy in Late Antiquity, which reached across Upper Mesopotamia toward the Khabur river and north to the lower districts of Armenia.
During his reign he embarked on a vast program of expansion, first conquering the peoples to the north in Asia Minor as far as Nairi and exacting tribute from Phrygia, then invading Aram (modern Syria) conquering the Aramaeans and neo Hittites between the Khabur and the Euphrates Rivers.
Diyar Rabī‘a encompasses the upper reaches of the river Khabur and its tributaries, i.e. the regions of Tur Abdin and Beth Arabaye, as well as both shores of the river Tigris from the vicinity of Jazirat ibn Umar in the north to the boundary with Iraq in the area of Tikrit in the south, including the lower reaches of the Upper Zab and Lower Zab.
The Euphrates originates in Turkey, is augmented by the Balikh and Khabur rivers in Syria, and enters Iraq in the northwest.
This region is watered by two tributaries to the Euphrates, the Balikh and the Khabur.
He was also the first to excavate archaeological sites in the Balikh Valley, to the west of the Khabur basin.
Its exact location is still unknown, although it is speculated to be in the Khabur region.