Watch List notes:

ABBASID: al-Ma'mun, 810-833, AR dirham (3.29g), Samarqand, AH203, A-224, citing 'Ali b. Musa al-Rida, recognized as heir by al-Ma'mun, representing his attempt to establish peace and cooperation between the Sunni and Shi'a branches of Islam, also citing the vizier Dhu'l-Ri'asatayn, minor central weakness, EF.

Estimate: 500-700 USD