The Byzantine Empire issued the gold solidus, or nomisma, used primarily for large transactions such as tax payments, and several denominations of copper coins, the money of daily business transactions. Mints in Antioch and Alexandria supplied the majority of the coinage circulated in the southern provinces. The newly established Arab government inherited an efficient monetary system and made few changes during its first decades. The caliph ‘Abd al-Malik (r. 685–705) introduced several issues of distinctively Islamic coinage. During the first decades of Islamic rule, Byzantine and newly minted Arab coins circulated together. The new coinage imitated Byzantine prototypes. Research has shown that these coins, without date or mintmark, were struck according to the declining weight standard of contemporary Byzantine coinage. This coin combines the commonly found Constans II imagery with the Arabic inscriptions muh[ammad] and ba‘d ("a part"—i.e., a fractional denomination). The identity of Muhammad, a name that is included on either the obverse or reverse of this type, has not been determined.
Inscription: In Arabic, on obverse: Muhammad; on reverse, in Greek: M; in exergue, in Arabic: bad [apparently meaning “a part,” that is, a fractional denomination]
New York. The Metropolitan Museum of Art. "Byzantium and Islam: Age of Transition (7th–9th Century)," March 12, 2012–July 8, 2012.