Watch List notes:

ABBASID: al-Ma 'mun, 810-833, AR dirham (2.96g), Madinat Isbahan, AH204, A-224, citing 'Ali b. Musa al-Rida, recognized as heir by al-Ma 'mun, representing al-Ma 'mun 's attempt to establish peace and cooperation between the Sunni and Shi 'a branches of Islam, also citing the vizier Dhu 'l-Ri 'asatayn, VF, R.

Estimate: 400-500 USD