Adiabene (Α᾿διαβηνή, sc. χώρα, probably from the river Zab or Diab), the principal of the six provinces into which Assyria was divided. Pliny (Hist. Nat. 5, 12) and Ammianus (23, 6, § 20) comprehend the whole of Assyria under this name, which, however, properly denoted only the province which was watered by the rivers Diab and Adiab, or the Great and Little Zab (Dhab), which flow into the Tigris below Nineveh (Mosul), from the north-east. The queen of this region, Helena, and her son Izates, who became converts to Judaism, are very often named by Josephus (Ant. 20: 2, 4; War, 2: 16, 19; 5: 4, 6, 11).