So now the one pound coin has had a dramatic makeover in order to make it harder to counterfeit. It's amazing to think that about 1 in 30 of the old pound coins in circulation were fakes. I never noticed, but then the point of a good forgery is that it is difficult to detect. Counterfeiting coins is a problem that governments have been facing for as long as they have issued official coinage. Lets look at some Roman examples...
On popular way to forge high value coins throughout the Roman Republic and Empire was to cover copper discs in a layer of silver before striking the coin. The coin would have appeared to be solid silver, but would actually be worth a lot less. Numismatists (coin experts) call these coins foureé (French for stuffed), and there are examples dating back to the first coins in Asia Minor. This type of counterfeiting could go unnoticed for years, if the silver was thick enough and the quality of the struck image good enough, as the coins would have appeared to be official currency until the silver layer was damaged or worn away by use.
A fake denarius from around 118BC
Across Britain, Gaul and Germany it is common to find ancient forgeries of copper small change. These forgeries can often be detected by the fact that part of the legend is in retrograde (that is to say, the letters are the mirror image of what they should be), which means that the coin was not struck with an official Roman die, but one made by someone who didn't know they needed to cut the letters in mirror image. As these coins are so low value, and don't pretend to be worth more than an official coin of that size, it seems that the provincial people on the edge of the Roman Empire were trying to make up for a lack of official coinage. Out on the frontiers, far from official mints, it would have been easy to run out of the small change that was essential for everyday trade. It seems that some forgeries at least were simply keeping local traders supplied with small change rather than trying to make a profit.
A hoard of fake Roman coins on display at the British Museum, Room 68