This unique coin carries the inscription offa rex, showing that it was made for Offa, king of Mercia (reigned 757–796).
The design is directly copied from a dinar coin of Offa’s contemporary, the Abbasid caliph al-Mansur (ah 136–58/ad 754–775). It is closely enough copied to identify not only the ruler but also the date of the coin from which this design was copied, which was issued in ah 157 (ad 773–74). However, it is clear that the die-cutter did not read Arabic, as minor errors have been introduced into the Arabic inscription, which is upside down in relation to Offa’s name and title.
The coin was first recorded in a saleroom in Rome, and may have been found there. It might have been a gift to the pope from Offa, as the Mercian king had promised to send him 365 gold coins every year. If the coin was part of such a diplomatic gift it is ironic that the copied Arabic inscription includes the statement that ‘there is no God but Allah alone’, part of the shahadah (Islamic declaration of faith).
The choice of an Islamic dinar as a model for Offa’s gold coinage should not be interpreted as an indication of Offa’s religious beliefs, as other evidence leaves no doubt that he was Christian. The coin probably reflects instead the importance of the gold dinar in international trade. It was the dominant coinage in the Mediterranean, and inspired the reintroduction of gold coinage in northern Europe.