Arbayistan

Arbāyistān (Parthian: 𐭀𐭓𐭁𐭉𐭎𐭕𐭍𐭉‎, romanized: [ʾrby]stny; Middle Persian: Arbāyistān, Arāwastān, Arwāstān; Armenian: Arvastan) or Beth Arabaye (Syriac: Bēṯ ʿArbāyē) was a Sasanian province in Late Antiquity. Due to its situation and its road systems, the province was a source of income from commercial traffic, as well as a constant area of contention during the Roman–Persian Wars.

The province reached across Upper Mesopotamia toward the Khabur and north to the lower districts of Armenia; it bordered Adiabene in the east, Armenia in the north and Asoristan in the south. On the west, it bordered the Roman provinces of Osroene and Mesopotamia. The principal city of the Arbayistan province was Nisibis and it also included the fortress of Sisauranon.