I thought the word penny derived from the Roman denarius, but apparently it was originally the pending, named for Penda, king of Mercia (d. 654) although established as a stable national currency by Offa a century later. Or so says P.J. Helm.
More curiously, in 774 Offa issued a gold coin, worth 30 silver pennies, with the words Offa Rex on the reverse but on the obverse an Arabic script taken from a dinar of Al-Mansur. It seems the Arabs at this time were known not only for preserving and furthering the scientific, medical and mathematical knowledge of the Greco-Roman world, but also for their gold coinage. Thus, even in Britain, it was felt that a gold coin had to feature Arabic script to be real.