Erbil, the chief town of Adiabene, lost much of its former importance with the growth of the city of Mosul, and during the reign of the patriarch Timothy I (780-823) the seat of the metropolitans of Adiabene was moved to Mosul.
A number of East Syrian bishops are attested between the eighth and 13th centuries for the diocese of Hebton, a region of northwest Adiabene to the south of the Great Zab, adjacent to the district of Marga.