The Islamic silver dirham was modeled after the drachm of the Sassanid empire. As a unit of account it was introduced in 632 already, shortly after the death of the Prophet Mohammed. Issued, however, were dirhams only under Abd al-Malik, the fifth Umayyad Caliph. In his coinage reform of 698 he extended the Islamic ban on depicting God and his creatures to coins. The dirham spread throughout the whole Caliphate from Bactria to Spain and was produced in many mints. It underwent its greatest dissemination from 800 to 1012. The term "dirham" lives on to this day in the currencies of Morocco and the United Arab Emirates.