Please answer the following question: I want to test the ability of students to read a passage and answer questions about it. Could you please come up with a good question for the passage "The various Germanic states in the west all had coinages that imitated existing Roman and Byzantine forms. Gold continued to be minted until the end of the 7th century, when it was replaced by silver coins. The basic Frankish silver coin was the denarius or denier, while the Anglo-Saxon version was called a penny. From these areas, the denier or penny spread throughout Europe during the centuries from 700 to 1000. Copper or bronze coins were not struck, nor were gold except in Southern Europe. No silver coins denominated in multiple units were minted."?
A:
Whose money did the Germanic states base their currency on?