A Roman Republican denarius of the early first century BC lies on its side in a tray, and across the goddess's cheek runs a short, deliberate gash. Someone made that cut with a chisel, long after the coin was struck and long before it reached any collection. Where the blade went in, the silver parts like a thin skin, and underneath it the metal is the dull red of copper.
This is a fourrée, or plated coin: a copper core wrapped in a silver foil and then struck between real dies, so that from the outside it carries every detail of an honest denarius. Most were probably made by private forgers, who stood to gain the difference between a disc of silver and a disc of copper. Whether all of them were private is a harder question. Pliny the Elder records that the tribune Livius Drusus, around 91 BC, mixed an eighth part of bronze into the silver, and some historians have read that line as evidence that the Roman state itself issued plated coins in moments of strain. Others think Pliny was describing an alloy, not plating, and that the official mint had no part in it. The evidence does not settle the matter.
What the cut does settle is that someone, at some point, did not trust this coin. Test cuts like this one turn up again and again on Republican silver, and they are especially common on coins found far from Rome, in hoards from Gaul and beyond, where a stranger's denarius had to prove itself before anyone would accept it. A chisel was the simplest instrument of doubt available: one stroke, and the inside of the coin had to answer for the outside.
Rome also tried to answer the question with law. Around 85 BC the praetor Marcus Marius Gratidianus published an edict on the coinage, and Cicero tells us the people were so grateful that statues of him appeared in the streets, with candles and incense set before them. What the edict actually required is uncertain. Pliny connects it to the testing of denarii, and many scholars accept that, but the text of the edict itself has not survived. Three years later Gratidianus was killed in the Sullan proscriptions, and his statues came down with him.
The serrated denarius, with its notched edge, is often explained as another defence against plating, since a notch would expose a copper core. It is a tidy explanation, and possibly a true one, but plated serrated coins exist too, which suggests the forgers simply learned to notch their own.
What stays with me about this coin is that the cut is the most honest thing on it. The design was made to persuade; the cut was made to find out. Somewhere, a person held this disc and chose suspicion over appearance, and the mark of that choice has lasted exactly as long as the image it was meant to question.