Watch List notes:

ISLAMIC, 'Abbasid Caliphate. Al-Mahdi, AH 158-169 / AD 775-785. Dirham (Silver, 25 mm, 2.89 g, 4 h), citing al-Mahdi as 'al- Khalifa al-Mahdi', Harun as the heir apparent and the governor Hasan., Harunabad (Armenia), AH 168 = 784. SICA III, -. A very attractive example. Good very fine.