Striking coins in Rome

Ancient Roman coins were made out of round discs of flat pressed metal, known as ‘mints’. That word is another from the Romans. There were two methods initiating the minting process, the coins could either be made by cold striking metal or hot striking.

Incredibly rare Roman die used in striking coins. It has a silver denarius of Tiberius still lodged in it. The reverse die, made of a hard bell-metal, was rendered useless by the stuck denarius. The mint worker tried to dislodge the coin, as marks show, before discarding the die. Est $15,000, it sold for $50,000 in 2009.

Official coin dies were subject to strict security to avoid counterfeiting and were destroyed at the end of their short lifespan. Stealing a coin die would result in certain painful death. The die came from the Roman mint at Lugdunum. While forger’s dies have survived from Roman times, only a handful of 'official' coin dies are known to exist. French researchers determined that 12 coin dies are official mint products; 11 of these are from the imperial mint of Lugdunum (modern Lyon) in France. Dies 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. 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.

Die engravers (sculptores) were highly skilled artisans who engraved the negative images (obverse and reverse) in hardened bronze or iron. A continuous supply of new dies was required. Many errors occurred while striking the coins.

The minting process started with the raw material. In many cases this was an alloy. For silver, using the wrong alloy generated quality problems. The striking team comprised a worker (suppostor) who placed the blank on the lower die, an aligner (signator) held the upper and lower dies in place, and a striker (malleator) hammered the top die to transfer the design.

Julius Caesar Denarius, struck in January 44 B.C. The first time a Roman leader appeared on coinage.

Minted in 46 BCE by the moneyer T. Carisius, this specific denarius is one of the most highly sought-after artifacts for understanding Roman coin making and metallurgy. It offers a direct, visual blueprint of the ancient coining process. Its reverse depicts ancient coining, showcasing an anvil, tongs, a hammer, and a garlanded die.