Islamic - Early Post-Reform,ABBASID: al-Mahdi, 775-785, AR dirham (3.00g), al-Yamama, AH168, A-215.1, citing the governor Abd Allah b. Said, with an extra letter after the name Said, some light hornsilver on the obverse, VF, RR. Al-Yamama was the first mint in Arabia to strike silver coins, located near the modern city of Riyadh, with its administrative capital at the town of Hajar. It operated AH165-170.