ISLAMIC, 'Abbasid Caliphate. temp. Al-Mahdi, AH 158-169 / AD 775-785. Hemidrachm (Silver, 24 mm, 1.93 g, 2 h), citing governor Yahya [ibn Mikhnaq] (PYE 128-130 = AD 779-781), Tabaristan, PYE 129 = AD 780. Draped Sasanian-style bust to right, wearing an elaborate crown; behind head, ‘GDE / ʾp̄zwt’ (‘[may his] glory increase’ in Pahlavi); before head, ‘Yaḥyā’ (‘Yahya’ in Arabic); in the outer margin to left and right, ‘nywk' ˗ ʾp̄d’ (‘good ˗ wonderful’ in Pahlavi). Rev. Fire altar, flanked by two attendants; above altar, star and crescent; to left, date in Pahlavi; to right, ‘tpwlstʾn’ (‘Tabaristan’ in Pahlavi). Album 60. Very rare. Brushed and with areas of weakness, otherwise, about extremely fine.