slamic Coinage — ʿAbbasid Caliphate, Time of al-MahdīCaliph: al-Mahdī (AH 158–169 / AD 775–785)Governor named: ʿUmar ibn al-ʿAlāʾ, Governor of Tabaristan (AH 154–163 / AD 771–780)Denomination: AR Hemidrachm (Silver)Mint: TabaristanDate: PYE 127 = AH 162 / AD 778–779Weight: 1.90 gDiameter: 23 mmReference: Album 56________________________________________ObverseCrowned and draped Sasanian-style bust facing right.Behind the head, Pahlavi legend:AFZUT GDH(“May his glory increase�...