A question regarding the Centenionalis. I'm looking to buy an affordable late silver/billion Roman coin (later than the Gordian III I just bought), and have been looking at a range of options. Interestingly, many sellers state that the Centenionalis is billion. However, when I read up about it, some sources state it is bronze, while others state it is billon (with very low silver content). So, is it bronze? Or billon? Or either or, depending on the time period? Also, what is the expected weight range for a Centenionalis?
Numiswiki is often a good place to look for answers to questions involving definitisions. https://www.forumancientcoins.com/numiswiki/view.asp?key=Centenionalis "Centenionalis Roman bronze currency used in mid 4th Century, usually depicts the common Fel Temp, fallen horseman type." Also on FAC, Rasiel Suarez's page on denominations (from his ERIC: The Encyclopedia of Roman Imperial Coins) is another page worth reading a bookmarking. He gives a succinct run through of Roman denominations over time. Apparently use of the word centenionalis is not universally accepted and I'd guess and consensus about what the metal content "should" be is probably also not agreed upon. If your goal is to buy a silver coin of the later Roman Imperial era, a centenionalis does not sound like the way to go.
If I understand what you are wanting to show here, I suggest you get a later period antoninianus of Aurelian through the Tetrarchy showing XXI in exergue indicating an alloy of 1 part silver and 20 parts copper. Following that you might want a silvered fallin horseman of the AE2 size which contained even less silver. You can decide when the silver was so low that you stop calling it billon. After Gallienus most 'silver' coins needed a silver was to remind people there was a bit of silver in the alloy. We usually call these AE or bronze but the fact remains there was silver in the mix. Aurelian XXI with silver wash partially remaining Constantius II with less silver (2%???) also with silver wash At the same time as the earliest falling horseman the mint issued a second denomination with about half the silver with left facing busts and several reverses. I don't have one of these with retained silver was to show but alloy tests have shown there is a bit there. No one calls these last two billon but they are 'silver' bearing.
Thanks for the responses. So the centenionalis isn't necessarily an accepted/universal term. Thanks for the suggestion @dougsmit It looks like you can get a quality XXI Aurelian for a decent price, like this one:
"It looks like you can get a quality XXI Aurelian for a decent price, like this one:" The coin pictured above is Probus. But yes, you can find very nice examples of coins of Probus and Aurelian at reasonable prices. This denomination is usually called the antoninianus, sometimes called a double denarius. These are from the late 3rd century. The centenionalis, also called the AE2, (AE for bronze, 2 for 1/2-sized module; there are also AE1s, AE3s and AE4s), is from the mid 4th century. There are also many fines examples of this type available, also at very reasonable prices. Constans Caesar, A.D. 333-337 Augustus, A.D. 337-350 (Bronze) AE2 Siscia mint, A.D. 348-359 (2nd series) Obv: D N CONSTA-NS P F AVGA behind obverse bust Rev: FEL TEMP RE-PARTIO - Soldier spearing fallen enemy horseman [dot]ASIS[dot] in exergue; A in left field RIC 254 24mm, 5.1g.
I can't say I have ever heard this expressed as a fraction but I guess that works reasonably well. In my photo below the AE3 is resting on a US cent for scale. For the record: Roman coins are AE4 no matter how small they got. The scale of coin sizes used by many people to describe late Roman bronze (including silvered bronze) coins when the correct denomination name is not certain. This can be used for any coin after the reform of Diocletian (follis, centenionalis or whatever). The system uses the abbreviation for bronze followed by a number 1 through 4: AE1 = over 25mm (Valentinian I); AE2 = 21-25mm (Honorius); AE3 = 17-21mm (Arcadius); AE4 = under 17mm (Theodosius I). Of course, there are still coin issues that straddle the lines with various specimens being, for example, slightly over or under 17mm. In this case you see a split listing 'AE3/4'. Mint workers placed little importance in exact diameter or roundness; if anything was important it was weight. All four sizes were rarely produced together and the system fails to separate the two sizes of AE2 'centenionales'. However imperfect, this system will have a place in describing late Roman coins until all denomination systems are understood. Care should be taken to separate these listings from the millimeter scale used for Greek coins where AE20 is a coin of 20mm diameter. There should be no confusion here since the smallest AE coins are over 4mm diameter.
I also suggest getting a later period Antoninianus to exemplify a silver-washed coin, though some folles of Diocletian and the tetrarchs also had a silver wash. As far as I know there is no definitive knowledge of what these coins were called by the romans. I have heard both "follis" and "nummus" bandied about, as well as "centenionalis" and "majorina". It's also unclear as to how the coins were tariffed. How many bronze coins of Theodosius equaled a solidus? How many "folles" of Diocletian equaled an aureus? In later years with the predominance of tiny bronze coins is significant and they must have been struck in vast quantities to serve as the small change for every day romans. One of the sources for the reign of Diocletian is the famous edict on maximum wages and prices, the penalty for abrogating the edict was death. It was designed to stop rampant inflation, but apparently was not successful, and seems to have been little enforced.
Is there evidence that there was a fixed exchange between the metals rather than a market that traded on an ever changing basis? Coins were not usually marked with a denomination. Some people attribute the M in the field of later coins of Constantius II as a sign that they were worth 1/1000th of a solidus. There are coins of a short time earlier that are marked LXXII and weigh 1/72 of a Roman pound. My example is a Constantius Gallus. Of course it is possible that both were just experiments since most coins of the day were not marked. Of course the FTR coin to end all FTR coins is the one in the British Museum with the large M alone as a reverse type. If I had that one I would feel guilty not giving it to Randy (our CT FTR guru) so it is good that I don't.
A very educational thread, I may have even learned something! Thank you all for the information and suggestions
There probably was a specific ratio of bronze coins to solidi in the late 4th and 5th centuries, but from a practical standpoint, it was meaningless. This late in the empire gold just did not circulate much, if at all. Most of the time it was just sent off to the Huns to keep them from invading, where it tended to get hoarded. That's why today it's actually easier to find near-pristine late-Imperial and early-Byzantine gold coins than well worn ones.
