When King Offa of England's Mercia decided to mint some coins, the coins which came to everyone's minds were the islamic dinars.
That's why his coins were identical to Dinars, with OFFA REX next to the islamic shahada.
https://artofthemiddleages.com/files/original/e5a8cb4eadae18...
https://www.islamic-awareness.org/history/islam/coins/dinar1