Looking at pictures of As coins I wondered if counterfeiting was common and, if not, why not? What measures could be used to combat counterfeiting? The coins themselves (normally) had a value that exceeded the intrinsic value of the metals, particularly bronze coins. They aren't particularly elaborate so it seems like any metal-worker should have been able to produce legitimate-looking fake coins.

If you happen to know the history of counterfeiting from another time and place, please share that as well!