How were ancient Roman coins made?

Ancient Roman coins were made out of round discs of flat pressed metal, also known as ‘mints’. There were two diverse methods initiating the minting process, the coins could either be made by cold striking metal or hot striking metal. The former method struck coins out of a cold sheet of metal, creating flat round discs which could then be pounded with a metal anvil if necessary to flatten the discs further. If using heat in the process, the metal would be heated (in a fire or furnace) and when liquid, poured into moulds. Or the metal could be softened and then rolled out into sheets and pounded into shape.

Once the mint discs had been produced the coins were marked with stamps, also called ‘dies’. These weighty stamps were made of bronze and iron and engraved with all of the details wanted on the coin. These were pounded onto the mint to leave an imprint of the design. For the different images on each side, the obverse and reverse, a hinged die was used. One image was attached to the top and one to the bottom, allowing for an efficient process where the flattened mint was placed between the dies, then clamped shut and pounded to transfer the images.

Mistakes in the Minting Process

This hoard is not just noteworthy for the sheer number of coins and the various images displayed, but also for the interesting faults that some of them display, allowing us an insider’s view into the coin making process and what can go wrong with a lack of skill or attention.

Try and spot the mistakes in the minting process on these coins, what could have happened to create these images?

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Countermarks are also visible on some of these coins.

What are countermarks?

These small marks usually take the form of letters and could represent the initial of an official who is verifying the value of older currency. These designs were added after the coin had been initially struck. Single and multiple letters were one of the most common types of countermarks, but they could also take the form of inanimate objects, figures of deities, or animals, to name a few examples. The marking is sunken into the coin, allowing it to be prominent and rise above the original background design. There could have been many potential purposes of countermarking, most probably including provision of new currency and the revaluation of pre-existing currency.

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