Watch List notes:

ISLAMIC, 'Abbasid Caliphate. al-Mahdi. AH 158-169 / AD 775-785. AR Dirham (25.5mm, 2.89 g, 12h). Citing al-khalifa al-mahdi. Madinat al-Salam (Baghdad) mint. Dated AH 160 (AD 776/7). Album 215.1; ICV 379. Light iridescent toning, slight peripheral weakness. Good VF.