Reinaud thought of the Seleucid era, which is not impossible; but Halevy observes that the fortress of Mawiyyat (now Hisn Ghorab) bears the date 640, and is said to have been erected " when the Abyssinians overran the country and destroyed the king of Himyar and his princes."
The early Moslem geographers knew it as Hisn Ziyad, but the Armenian name was Khartabirt or Kharbirt, whence Kharput.