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Unique Ancient Coins

What I Like about Unique Ancient Coins

One of the things I like about ancient coins is that it's possible to find a coin that's unique, unlisted, new to collectors, and previously unknown. (Am I being repetitively tautological here?) But you will need to have patience, pay attention to what's around you, and make good use of reference books.

And there's an important question to decide – how much unlike other coins does one have to be to count as unique? Most Roman coins show lots of variation in a single type of coin. On my hut coins page, I have a whole page of varieties of just one coin. But apart from this, there are several classes, or types, of coin within which unique coins can easily be found.

Barbarous Imitations

Most unique ancient coins belong to two classes of coins: barbarous or faked imitations of official coins.

Barbarous Roman coins were made by the local inhabitants around the edges of the Empire, perhaps to act as semi-legitimate currency in the absence of an adequate supply of officially minted coins, or perhaps so that the local tribes could maintain a degree of indepencence. These coins normally imitate late Roman bronzes, and if you want to find a unique barbarous imitation of a Tetricus or Claudius II coin, you won't find it hard. The first three coins below are of this "unofficial" type, copying coins of Magnentius and Carausius.

A Barbarous bronze coin imitating Magnentius A barbarous bronze coin imitating Magnentius. It weighs 1.14 grammes and is 15mm x 13mm across.

This small coin imitates a larger coin of Magnentius. The hairstyle is more or less correct, but the rest of the portrait is well away from the official style. The reverse is also a poor copy, and the legends aren't quite right either. The writing on the shield is particularly off – it should say "VOT V MVLT X" across four lines, and it actually says "OT ILT" across two.

There are a lot of coins around that are rather like this, but one with the exact same errors is unlikely – so this coin is probably unique, but at the same time, it's quite like a lot of other coins.

A barbarous bronze coin imitating Magnentius A Barbarous imitation of a Magnentius bronze. It weighs 3.8 grammes and is 19 x 21mm across.

For example, this is another "unofficial" imitation, complete with a copied Trier mintmark. The huge eye gives it away immediately, and there are also irregularities in the lettering and the labarum. It's nice, though, and in quite good condition. This one was found by a detectorist in Lincolnshire.

A barbarous bronze coin probably imitating Carausius A barbarous bronze probably imitating Carausius. It weighs 2.32 grammes and is 19mm across.

In this case, the coin is even further away from the official design, and although you would be able to find coins with similar styles, they won't quite match this one. The letters of the legend have been treated more as design elements than as writing. Look at the "S" on its side on the reverse – echoing the wriggling snake – and the way the legend starts off the word SALVS but degenerates into nothing recognisable very quickly.

You can see Salus standing, holding a shallow dish, and the snake reaching up to it. Salus is clearly holding a tall sceptre. The swirls in the design were, in the original, drapes of clothing. You can see some official coins to compare with this on my Salus page, which also includes another barbarous Salus.

Ancient Fakes

Coins that are definitely, obviously ancient fakes are also often unique. Fourées, coins with a base metal core and a shiny coating, are good examples. Some of these are very hard to tell from the original coins they were copied from, but that is certainly not true of this one:

A contemporary forgery of a coin of Julia Mamaea A silver and billon fourée of Julia Mamaea. It weighs 1.9 grammes and is 17mm across. The obverse legend is IVLIA MA-IMAE AVG, the reverse is LIBERTAS AVGVSTI.
Detail from a contemporary forgery of a coin of Julia Mamaea Crude letter B

This is an out-and-out ancient fake, a poor effort at reproducing a silver denarius of Julia Mamaea. The style is crude, the core is bronze with some silver content instead of all silver, and the legend is wrong too. The inset at the right shows the crude rendering of the letter "B" and the cap of freedom on the reverse. The chances of you finding another like this are minute. And this cost me only $9.99 on eBay!

Actually, I probably should not call this coin a fourée. A true fourée has a coating of silver (or gold) metal over a base metal core, and the two layers are fused together when the coin is struck. This particular coin looks as though it has some silver content in the metal, and the way it has been processed and struck has brought out a purer silvery surface.

That's a rather different technique for producing a similar end result – and the coin is just as much a fake.

Striking Errors

By which I mean, mistakes were made when some coins were struck. Sometimes coins just didn't come out the way they were intended. There are several types of striking error you might come across. For example, brockages, where a coin has stuck to the die and the next coin gets an impression of that coin instead of the die. Each individual brockage is most likely unique.

A brockage bronze coin of Arcadius A small bronze coin of Arcadius. It weighs 2.4 grammes and is 7mm across. The obverse legend is D N ARCADIVS P F AVG.

This little coin is a very clear brockage. A reversed image of the emperor's head has been struck onto the reverse of the coin, and there are traces of a reversed legend around the edge. There are no signs of any other design on the coin, so the actual reverse die has never touched it. A coin must have stuck, unnoticed, to the top part of the die when it was lifted off the anvil, and then impressed itself instead of the die onto the next blank coin, which was this one.

A reverse brockage bronze coin perhaps of Tetricus I A billon antoninianus, 3rd century CE. It weighs 2.2 grammes and is 17m x 19mm across. The reverse legend is LAETITIA AVG N.

This is a reverse brockage, a much less common phenomenon. For this to happen, a coin would have to be left on the lower part of the die and another blank placed on top of it and then struck. This must have been obvious to the workers, so either they were working so fast and automatically that they didn't have time to correct their error, or they didn't care. Or a combination of the two. Perhaps there was pressure to turn coins out in volume.

A denarius of Julia Domna with a massive die clash A silver denarius of Julia Domna. It weighs 2.4 grammes and is 16mm x 18mm across. The obverse legend is IVLIA DO - MNA AVG, the reverse should be VENERI VICTR

But not every striking error is actually unique. Here's something that's deceptive:

This looks like a brockage that has been re-struck, but it's actually a die clash. The dies have been struck together at some stage without there being a blank coin in place. This has damaged the reverse die and resulted in all subsequent coins being struck with the impression you see here, an upside-down image of the obverse of the coin.

How do I know for sure that this is a die clash? Because I know for sure it's not unique. Doug Smith has two of these and knows of a fourth. If it were a brockage, each coin would differ from the others, even if only in small ways. Apart from the shapes of the flans, and the amount of wear, these are identical.

A denarius of Elagabalus with a clear double strike A silver denarius of Elagabalus. It weighs 2.9 grammes and is 18mm x 20mm across. The obverse legend is IMP ANTONINVS AVG, the reverse is SPEI PERPETVAE.

Here is a link to Doug's page showing his coins, to which I give full credit for this explanation. Doug's page contains a good deal of useful information about die clashes and brockages, and in fact if I hadn't read that page I wouldn't have recognised the significance of this interesting coin when I saw it on eBay.

This is a quite different error – a double strike. The die has been hammered twice while the coin was in place, and the coin has moved relative to the obverse die in between the strikes, resulting in a rather disconcerting image. Double strikes are all unique, but they're common enough that they aren't very remarkable.


Sometimes, coins were made by striking a new image onto a coin of a previous ruler. This has happened now and again ever since coins were first made. The advantages are twofold: you have a ready-made flan that's the right shape and weight, and you get rid of evidence that the last ruler existed. The disadvantage is that you often leave a trace of the previous design on the coin, in areas where the new die does not strike the surface very strongly. This produces lots of unique coins with interesting puzzles built in. Sometimes overstrikes were done en masse, but there are also plenty of oddities to be found.

A bronze coin of Arcadius overstruck on a coin of Valentinian II A bronze AE2 of Arcadius, 383-408 CE, overstruck on a bronze AE2 of Valentinian II, 375-392 CE.
Arcadius overstrike Valentinian II original The reverse of a bronze coin of Arcadius overstruck on a coin of Valentinian II with a Valentinian II obverse for comparison The obverse of the same bronze coin rotated to show the undertype, with a Valentinian II reverse for comparison.

Here is an unusual example. The "top" coin, the most recently struck, is a VIRTVS EXERCITI coin of Arcadius. Underneath is a "REPARATIO REIPVB" of Valentinian II, showing the emperor raising a kneeling, crowned female figure. The reigns of these emperors overlapped, and there's no obvious reason why one coin should be struck over the other.

On the right I have shown the obverse of this coin and the reverse of the base coin. I have rotated the overstruck coin so that it matches the design on the other coin, and you can clearly see that the whole top left quarter hasn't taken the second impression at all, and the original legend, the head of the emperor, and the crown and head of the kneeling figure are all quite plainly visible. The reverse shows a similar mixture.

This coin was sold on eBay with a full description, including a note that it is possibly unique, and the final price was $4.00. So uniqeness can be very affordable if you don't mind ugliness! A pretty unique coin would cost a lot more.

You will also have spotted that this coin has a hole in it ...

Holed Coins

Most of the coins on this page are unique because of circumstances up to and including their being struck. Quite often, you will find coins for sale in which holes have been bored after they entered circulation. These, too, are all unique, though many people will not count them as collectible, because anyone can deface a coin. The thing about a hole, though, is that it indicates that some unusual use was made of the coin in ancient times, and thus it can give clues to an interesting history. I have a page about holed ancient coins, and here is the start of a gallery of holed coins.

Banker's Marks

Another thing that can happen to a coin after it is circulated is that it might be tested for purity or for genuineness. Many silver coins show the marks of test punches designed to prove that the coin is not a fourée, and is in fact silver all the way through. These marks can often deface a coin, but they can also add to its interest. Such coins have often been traded across borders and gone through the hands of the money-changers who were the ancient equivalent of international banks.

A tetradrachm of Ptolemy II with banker's marks A silver tetradrachm of Ptolemy II, year 8 = 276-275 BCE. Tyre mint. The (reverse) legend is ΒΑΣΙΛEΩΣ ΠΤΟΛEΜΑΙΟΥ. One of the banker's marks is inset on the right.
Banker's mark on Ptolemy II tetradrachm Banker's mark.

These men might also punch their own design into a coin, or make a particular scratch on it, so that they could tell if it had passed through their hands before.

This chunky silver coin is covered with test punches, scratches and banker's marks. One of the more interesting marks is enlarged on the right. Above it is part of a scratch mark, also placed by an ancient banker.

This coin was relatively cheap to buy, because all the punches make quite a difference to its appearance. But with all these marks and tests, it could have travelled around the Western world, which gives it an interest that the bland, perfect coins do not have.

Legend Blunders

Sometimes the engraver just makes a mistake. Coins are produced which include the mistake, because making a new die costs money. Then most of them get lost over the centuries. If you have an official coin with a true legend blunder, and you're sure it's not a known variation which was produced on purpose or a barbarous imitation of an official coin, then it might easily be the only known example. Legend blunders as a class are quite frequent, if not exactly common, so your chances are good. I have collected these four over a period of 5 years, and I haven't been looking hard - these have just caught my eye.

A denarius of Hadrian with a legend blunder A silver denarius of Hadrian from 117 CE with a minor legend blunder. The obverse legend is IMP CAESAR TRAIAN HADRIANVS AVG. The reverse is PM TR P COS II with CONCORD in the exergue.
Detail of a legend blunder on a denarius of Hadrian Reversed R

On the reverse of this denarius, the R of CONCORD is back to front. This is probably an easy mistake to make when you are engraving a die that has to be a mirror image of the coin to be produced.

The reverse legend on this next coin, an antoninianus of Gallienus, should be PAX AVGG, and in fact it is PAA AVGG. In other examples, the X of PAX is placed below Pax's outstretched arm, so the engraver might simply have been used to placing the A of AVGG just above the arm, and made a careless mistake.

An antoninianus of Gallienus with a legend blunder PAA instead of PAX A billon antoninianus of Gallienus from 257-258 CE with a legend blunder. The obverse legend is IMP GALLIENVS P F AVG GM. The reverse is PAA AVGG.

But here I had a surprise coming. In late 2007 I unexpectedly came across another coin just like this, but from two different dies! It was on this excellent site, which specialises in coins of Gallienus.

On asking around, I found out that Curtis Clay (the expert's expert) had said of the coin on that site: "Surprisingly, this error was not confined to a single rev. die. The Eauze Hoard contained no fewer than seven PAA AVG coins like yours, and of those only two were die duplicates, so the seven coins were from six different obv. and six diff. rev. dies. The illustrated spec., pl. 70, 1287, is from different dies than yours." (Though I don't know whether any of those dies matches my own specimen).

When I first wrote this page, I put a warning at the end that a coin you believe to be unique might not be so forever. How true that is!

On the die for the coin below left, the engraver has simply left out the T from Herennia's surname. Maybe more of these are known, maybe not. It will only have happened on this one die, so "not" is quite likely.

Antoninianus of Herennia Etruscilla with a misspelt obverse legend. A silver antoninianus of Herennia Etruscilla with a legend blunder. The obverse legend is HER ERVSCILLA AVG. The reverse is PVDICITIA AVG.
Billon antoninianus of Gallienus with obverse and reverse legend blunders A billon antoninianus of Gallienus with obverse and reverse legend blunders. The obverse legend is IMP C P LIC GALLIAENVS P F AVG. The reverse is ORIENS AVS.

On the right is a double error, and an odd one. It's another Gallienus, but this time from a mint in Syria. On the obverse, the name has been spelt as "GALLIAENVS", and on the reverse, we have "AVS" instead of "AVG." Neither of these errors appear to be documented for this coin, so with two in one, this is very likely a unique specimen.

Detail of legend blunders on an antoninianus of Gallienus Legend errors on an antoninianus of Gallienus: GALLIHENVS for GALLIENUS and AVS for AVG.

That "GALLIAENVS" (or perhaps "GALLIHENUS") has a couple of possible explanations. The coin is from an Eastern mint, where Greek would have been spoken, so the H might have been a Greek Eta, and when the engraver saw his mistake, he just carried on. Or it might be an open-topped A, to spell out the name phonetically; but against this is the fact that the AE construction was Roman, not Greek.

But whichever is the case, this sort of error probably gives you the best chance of finding a unique coin which is an official issue in good condition and from an undamaged die.

Of all the coins on this page, the Herennia Etruscilla antoninianus two coins up gets the most attention. It's regarded as a rare and desirable error by collectors of that period, more so than the others I have shown because a Herennia error, in her name, and from the Rome mint, is much less likely. The obverse side of coins always had much more attention paid to it than the reverse, and was less prone to errors as a result.

Even so, the Herennia coin is certainly not worth a fortune. It cost me less than £18, and I found it by trawling eBay for interesting offers. Other similar errors known to exist include an Antioch antoninianus of Gordian III calling him GORIANVS, sold as one of a lot of three error coins in the Gemini sale in January 2008 (they fetched $250 for the three); and in the British Museum is an as of Galba calling him GABA, listed as BMC 149, which I expect is worth considerably more than that.

New Varieties

It's quite possible to find minor varieties of known official coins. If the variation is definite enough, you can count it as unique. Minor variations are common, and aren't thought of as remarkable. If you find a bust or reverse type that hasn't previously been seen, or a distinct major design variation, you could cause quite a stir. Major finds like this crop up every few years and are often immediately denounced as fakes ... here, for example, you can see a coin which has been the cause of much enjoyable controversy since it came to light in 2003 and was bought by Zach of Beast Coins.

The cream of this type of discovery would be a new Emperor .. and such discoveries do happen. Rebel generals and governors did sometimes declare themselves emperors and strike a few coins before being deposed. In 2003, a coin of the emperor Domitianus II was found in circumstances which showed it to be genuine. Only one previous coin of this emperor had been recorded, and it had been dismissed as a fake. Here's a British Museum page showing their electrotype copy of the 2003 Domitianus II coin.

Bronze fouree core of an antoninianus of Philip I A bronze fourée core of Philip I. It weighs 1.94 grammes and is 20mm across. The obverse legend is IMP M IVL PHILIPPVS (AVG) and the reverse is FORT REDVX.

Unfortunately I don't have anything of this nature of my own I can show you. But I can show something that looks like a unique new variety until the experts turn their eye on it – a fake unique coin! It looks like a bronze coin of Philip I. The style is good, the reverse looks OK, but no such bronze coin is listed in the reference books. In fact, it's the bronze core of another fourée. But no silver coin like this has been recorded either, so it seems to be a previously unknown fourée.

I found this in a batch of crusty coins, covered with a hard crust which had to be removed to find the coin inside. It's quite spongy inside because of corrosion, and the faked silver surface has been lost over time. It would have been imitating an antoninianus, but there weren't any official coins with this combination of features, so it's a mule, with the obverse and reverse imitating coins from the reigns of different emperors. This reverse is known from Gordian III's time. It's the legend that leads to this conclusion. Here it's FORT REDUX, but Philip I's coins only ever had the full text, FORTVNA REDUX. So .. regretfully .. this coin really belongs back up in the section on "ancient fakes."

Finding Unique Ancient Coins

To find a unique coin, you need to know a bit about the coins you're looking at, and you need to watch carefully on eBay, or go and dig through unsorted coin lots, or buy and clean lots of uncleaned coins. There are so many coins coming onto the market – tens of thousands every year – that it's quite certain that some of them will be unknown types. I've been collecting since 2002, and I'm pretty sure I've let more than one rarity or unique coin go through not knowing what I was doing. I'm a bit more cautious now.

A contemporary fake of a sestertius of Julia Domna A brass contemporary fake sestertius of Julia Domna. It weighs 16.5 grammes and is 28.5mm across. The obverse legend is (IVLIA AV)GVSTA, and the reverse is (MATRI MA)GNAE S C.

Here's another attempt on my part. I spotted this chunky but badly worn sestertius on eBay. It has a reverse showing Cybele, the Mother Goddess, seated facing right. All the references I could find showed similar coins, but with Cybele facing the other way. So I bought it. For an outlay of $6.50 it was worth the chance that it would be something interesting! And then I asked the assembled experts on Forvm if they could identify it.

Curtis Clay, one of the most knowledgeable experts around, and amazingly generous with his time, spotted it as an ancient fake .. this reverse was only used for Faustina Junior. But he also told me that Cohen and The Roman Imperial Coinage, both very standard references, referred to an example in Paris and mis-identified it as having a IVLIA DOMNA AVG obverse. (It still had to be a fake.) Curtis has a plaster cast of this Paris specimen, and it seems to him to be a double die match to mine. So, Cohen got it wrong, Curtis got it right, and I have a coin which, although not quite unique, is one of only two known specimens and has an interesting story behind it! (well, interesting to ancient coin collectors.)

(But in April 2008, a third specimen turned up, owned by a member of the Forum Classical Numismatics Discussion Board, a worn and holed coin which he had picked up from a dealer's junk box several years ago ... and I bet there are more out there too.)

Don't start thinking that you can make a fortune. Most unique ancient coins are of such common types that unless there's something else special about them, they will probably only be worth a few pounds or tens of pounds. This is even true of rarities like my Julia Domna sestertius; there are only two documented examples, so maybe only a handful in existence, but value depends on who wants it, and the market for anonymous ancient fakes is not that good.

Finally, please be aware that if you have a unique coin, it might not be unique forever. Someone might be holding another example in their hand right now!

The content of this page was last updated on 18 August 2010.

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