After the early Muslim conquests brought the nascent caliphate into contact with the numismatic traditions of the Byzantine Empire and the Sasanian Empire, whose lands they took over, the Islamic world developed its own, distinctive tradition of coinage.
Islamic currency consisted of gold (dinars), silver (dirhams), and copper or bronze (fals) coins, as well as their fractions and multiples.
Initially these coins followed pre-Islamic patterns in iconography, but under Caliph Abd al-Malik ibn Marwan, a distinctive Islamic dinar type was created that eschewed images and carried the Islamic profession of faith.
In the eastern parts of the caliphate, silver Arab–Sasanian coinage continued to be minted into the 9th century, before it was also replaced by Islamic patterns.
The right to mint coins in one's own name became one of the chief attributes of sovereingty in Islam, and as autonomous and independent dynasties multiplied with the break-up of the Abbasid Caliphate in the 10th century, distinctive styles and sub-currencies emerged in the various states and regions as they sought to differentiate themselves from the Abbasid standard (e.g. Fatimid coinage).