 The earliest of Beorhtwulf 's coins were issued in 841 – 842 , and can be identified as the work of a Rochester die @-@ cutter who also produced coins early in the reign of Æthelwulf of Wessex . After ten years without any coinage , Beorhtwulf would have had to go outside Mercia to find skilled die @-@ cutters , and Rochester was the closest mint . Hence the link to Rochester probably does not indicate that the coins were minted there ; it is more likely that they were produced in London , which was under Mercian control . Subsequent coins of Beorhtwulf 's are very similar to Æthelwulf 's . One coin combines a portrait of Beorhtwulf on the reverse side with a design used by Æthelwulf on the obverse ; this has been interpreted as indicating an alliance between the two kingdoms , but it is more likely to have been the work of a forger or an illiterate moneyer reusing the design of a coin of Æthelwulf 's . A different coinage appears later in the 840s , and was probably ended by the Viking attacks of 850 – 851 . There are also coins without portraits that are likely to have been produced at the very end of Beorhtwulf 's reign . 
