Watch List notes:

ABBASID: al-Ma'mun, 810-833, AR dirham (2.92g), al-Muhammadiya, AH199, A-223.4, citing the vizier Dhu'l-Ri'asatayn beneath reverse, and with extra symbol in obverse margin, perhaps the Arabic letter "S" or a word such as "bayt" ("house") of some other formal abbreviation, superb Extremely Fine to About Uncirculated.

Estimate: 200-240 USD