Ranking the emperors from most to least common

[rasiel]

https://docs.google.com/spreadsheets/d/12u-z0NWHyz1BwIqNjDeHreUxt9KathRxjNvaPhzq7G0/edit?gid=0#gid=0

The link above is to a spreadsheet ranking all the Roman emperors from Augustus to Romulus Augustus. This list pulls in data from over 1.2 million auction sales from Coryssa.org. No private sales are considered for this study, only public auctions. On the second tab there is an initial but not highly accurate list done for the Byzantine emperors (Arcadius - Constantine XI)

 

In this new version I'm introducing a new concept to group the entire series into five rings of exponential rarity. Ring 1 encompasses the most commonly found and represents a total of 90% of the market. Ring 2 are those within the rarest 10%. The group in Ring 3 are reserved for the 1% then Ring 4 the 0.1% and finally those in Ring 5 only a maximum of 0.01% of sales for the entire range highlighted in that color.

 

I hope to refine it further over the coming months. Please let me know your comments and suggestions. Enjoy!

Rasiel

[Postvmvs]

Thanks for sharing. One thing to consider is that this listing represents the most commonly sold (individually) emperors, but not the most commonly existing. For example coins of Tetricus are very common and were made in huge numbers as the coinage collapsed from debased silver to almost entirely base metal. So coins of Tetricus often aren't even worth being listed individually. Tetricus lands at #71 behind many scarcer emperors like Galba and Vitellius!

[Bonshaw]

53 minutes ago, rasiel said:

https://docs.google.com/spreadsheets/d/12u-z0NWHyz1BwIqNjDeHreUxt9KathRxjNvaPhzq7G0/edit?gid=0#gid=0

The link above is to a spreadsheet ranking all the Roman emperors from Augustus to Romulus Augustus. This list pulls in data from over 1.2 million auction sales from Coryssa.org. No private sales are considered for this study, only public auctions. On the second tab there is an initial but not highly accurate list done for the Byzantine emperors (Arcadius - Constantine XI)

 

In this new version I'm introducing a new concept to group the entire series into five rings of exponential rarity. Ring 1 encompasses the most commonly found and represents a total of 90% of the market. Ring 2 are those within the rarest 10%. The group in Ring 3 are reserved for the 1% then Ring 4 the 0.1% and finally those in Ring 5 only a maximum of 0.01% of sales for the entire range highlighted in that color.

 

I hope to refine it further over the coming months. Please let me know your comments and suggestions. Enjoy!

Rasiel

@rasiel,

This is a great service. Two questions:

1) Can you clarify your requirements for inclusion? I note you have Britannicus in there, who never actually ruled. Are officially recognized heirs included then?

2) Also, is your "market" only for imperial issues, as opposed to provincials, or both, if they come up on Coryssa?

- yr obt svt, Bonshaw

Edited August 12 by Bonshaw

[rasiel]

Yes, for all Roman imperial authorities (emperor, wife, caesars, etc.). No provincials or Republican. I also discard group lots, anonymous, coins that are damaged, uncertain, etc. The auctions mix together listings from all the major and minor auction houses as well as ebay going back to the 1800s. The purpose is to give an accurate picture of the market. However, it does not count coins listed for private sale (Vcoins, MA Shops, Ebay fixed price, etc.)

Rasiel

[Bonshaw]

15 minutes ago, rasiel said:

Yes, for all Roman imperial authorities (emperor, wife, caesars, etc.). No provincials or Republican. I also discard group lots, anonymous, coins that are damaged, uncertain, etc. The auctions mix together listings from all the major and minor auction houses as well as ebay going back to the 1800s. The purpose is to give an accurate picture of the market. However, it does not count coins listed for private sale (Vcoins, MA Shops, Ebay fixed price, etc.)

Rasiel

Perfectly clear. I would only suggest that you add this expanded explanation to the spreadsheet itself, perhaps in a separate tab.

[MrMonkeySwag96]

I’m surprised that coins of the Adoptive emperors are slightly more common than that of the Severan dynasty or 3rd Century Crisis era. I thought it was the other way around. 
 

Coins of Aquilia Severa are scarcer than I thought. She is currently the “rarest” of the individuals on this list in my Roman Imperial coin collection. 
 

 

 

Edited August 12 by MrMonkeySwag96

[GERMANICVS]

Very interesting, thank you!

I have a few in the "Blue Zone", yay!  No Yellows or Reds.....🙁

 

This list circulated a few years ago in CoinTalk (I think), it shows a similar pattern.

 

Roman_Ruler_RarityModified2.pdf

[John Conduitt]

Really helpful. It is always useful to have a view on just how scarce emperors are.
 

6 hours ago, Postvmvs said:

Thanks for sharing. One thing to consider is that this listing represents the most commonly sold (individually) emperors, but not the most commonly existing. For example coins of Tetricus are very common and were made in huge numbers as the coinage collapsed from debased silver to almost entirely base metal. So coins of Tetricus often aren't even worth being listed individually. Tetricus lands at #71 behind many scarcer emperors like Galba and Vitellius!

Yes it would be good if there was a way to add some sort of adjustment for cheap bronzes, the lack of which at auction seems to be heavily skewing the results. Otherwise it is a list of emperors you are likely to find sold individually at auction, not a list of emperors by rarity.

There is no way, for example, that Constantius II is only the 12th most common, and Nero is more common than Constantine II, Licinius I, Claudius II, Victorinus and Postumus. Tetricus II, Constantius Gallus, Procopius and Allectus are certainly not in the same bracket as Pupienus, Balbinus and Pertinax. On the other hand, the list does seem to pick out the rarest emperors well.

I used the Portable Antiquities Scheme database to rank emperors (although only for a certain period). This puts Constantius II, Tetricus I, Constantine II, Claudius II etc where you'd expect them, although it also has big limitations in that it is UK finds only (so the likes of Procopius and Theodosius II are rarer than expected) and I don't think even this deals with the really cheap bronzes, like Constantius Gallus (whose fallen horseman you have to study carefully to distinguish from Constantius II and Constans, if you can be bothered) or slugs of Augustus, which metal detectorists are not going to go to the trouble of reporting.

Edited August 12 by John Conduitt

[Salomons Cat]

Thanks @rasiel, very interesting.

8 hours ago, MrMonkeySwag96 said:

Coins of Aquilia Severa are scarcer than I thought. She is currently the “rarest” of the individuals on this list in my Roman Imperial coin collection. 

Same for me. Aquilia is also my rarest individual:

[Ancient Coin Hunter]

Pretty fascinating. I would have thought Gordian III was very common but apparently not. Gordian I and II are near the bottom of the list. Niger, ruling mostly in the East, is least common with 2 examples I see, tied with Gordian II.

Edited August 12 by Ancient Coin Hunter

[GERMANICVS]

46 minutes ago, Salomons Cat said:

Thanks @rasiel, very interesting.

Same for me. Aquilia is also my rarest individual:

One of my rarest for me too: 

 

Somehow, now she doesnt"t seem so rare....

 

 

[ela126]

i appreciate the Byzantine table. not a lot of love in that direction, you're a champion of that sector.

if there is an ability to do it, i think breaking out the J2 reigns, will show 2nd reign falls a bit lower on the list than currently reflected. i find when sharing coins its important to highlight the difference. 

[mrbreeze]

Thank you for posting this list.  It is much appreciated.

[CPK]

Nice list, but I don't see Sponsianus on it anywhere. 🤔

[Kali]

2 hours ago, GERMANICVS said:

One of my rarest for me too: 

 

Somehow, now she doesnt"t seem so rare....

 

 

I agree, she isn't.

But, I guess compared to all the "Julia's" from that period, she is.🙄


Aquilia Severa (220, & 221 - 222 A.D.)
AR Denarius
O: IVLIA AQUILIA SEVERA AVG, Draped bust right.
R: CONCORDIA, Concordia standing facing, head left, holding double cornucopia and sacrificing with patera over altar to left; star to right.
Rome Mint
19mm
3.02g
RIC IV(part 2), pg 47, #226 (Elagabalus)

Scarcer with "Star in Right Field".

[DonnaML]

As always, a fascinating chart. I guess my rarest according to this list are Aquilia Severa at 63 (which I've never thought of as being so rare) and Julia Titi at 67:

 

As well as Livia at 66, depending on whether her son's depictions of Pax and Pietas are counted as intended to represent Livia, on the so-called Tribute Penny denarius (and the equivalent bronzes) or on this dupondius:

If Provincials had been included, of course -- which I think perhaps would have given a more realistic picture of what's actually on the market and what actually circulated in much of the Roman Empire -- a lot of the greater rarities on this list would suddenly become much less scarce, and I would be able to add my examples of figures such as Domitia, Agrippina II, and Tranquillina.  

I also wonder if there's some way to break down the list between denarii and bronzes, to accurately reflect the divergence between the two in terms of relative scarcity for certain Emperors, such as Caligula and Claudius I -- very common in bronze, as opposed to scarce and expensive in silver.

 

[Coinmaster]

1 hour ago, DonnaML said:

 

I also wonder if there's some way to break down the list between denarii and bronzes, to accurately reflect the divergence between the two in terms of relative scarcity for certain Emperors

Yes, I agree and would love that too. I expect this can look different, as the denarii were most linked to military payments.

[Coinmaster]

10 hours ago, John Conduitt said:

I used the Portable Antiquities Scheme database to rank emperors

Also PAN and NUMIS in The Netherlands would be great to compare, as metal detecting is not only permitted but also there exist great cooperation with metal detectorists who helps recording their finds. The past few years there is a great increase in recorded finds because of this.

Also the records in the Oxford University project Coin Hoards of the Roman Empire (CHRE) could be of great use.

[rasiel]

It's important to note that the aim of this project aims to give an accurate picture of market rarity as opposed to absolute rarity. I wrote about the rationale ten years ago when I posted the first iteration which you can read if you want a deep dive: https://dirtyoldcoins.com/Roman-Coins-Blog/1267

The TLDR is that, no, neither Tetricus nor Constantius II are more common than they appear in this ranking. Or rather, the true figure of outstanding specimens in an absolute sense is unknowable - and more or less irrelevant. After all, even if there were literal truckloads of Eid Mars sitting in the vaults of the British Museum it wouldn't affect either their price nor the difficulty of getting one for yourself which is, after all, what matters most to you and me.

Rasiel

[John Conduitt]

9 hours ago, rasiel said:

It's important to note that the aim of this project aims to give an accurate picture of market rarity as opposed to absolute rarity. I wrote about the rationale ten years ago when I posted the first iteration which you can read if you want a deep dive: https://dirtyoldcoins.com/Roman-Coins-Blog/1267

The TLDR is that, no, neither Tetricus nor Constantius II are more common than they appear in this ranking. Or rather, the true figure of outstanding specimens in an absolute sense is unknowable - and more or less irrelevant. After all, even if there were literal truckloads of Eid Mars sitting in the vaults of the British Museum it wouldn't affect either their price nor the difficulty of getting one for yourself which is, after all, what matters most to you and me.

Rasiel

That's fair enough but might still miss the point that the market availability of Constantius II and Tetricus I (and many other emperors) is much, much higher than this method shows. I get the point about museum pieces not being available to buy, but museums did not buy the 11,000 individual Constantius IIs and 11,000 individual Tetricus Is that have been found and reported in the UK, let alone the hundreds of thousands (millions?) that were found elsewhere, haven't been reported or were part of large hoards. Those are mainly sold privately and/or on eBay. Indeed, it is the rarer coins that the museums buy, not the common ones.

The finder of the 3,000 coins in the Rauceby Hoard has sold numerous coins in the major auctions, but has sold many more privately, via dealers and on eBay. I believe he still has a couple of thousand left if you want one, none of which are in these numbers but are 'available to buy'. That would boost the totals for Diocletian, Maximian and Constantius I. These are among the emperors who are much more likely to have coins in large hoards than others e.g. Magnentius and Decentius vs Galba and Lucilla, and so are underreported in the list.

Another example is the Normanby Hoard of 50,000 coins found in 1985. That contained 16,000 of Tetricus I and 7,000 of Tetricus II. That's four times as many of Tetricus I and three times as many of Tetricus II as the list shows have been sold, just in one hoard. Are they all sat in a museum? Or does the finder have a huge pile they are not selling? No, they have been sold and are still widely available, just not in the major auctions. There are some on eBay right now. Coincraft has a large stock if you want one - so many they don't show the individual coins or even let you choose which of Victorinus, Tetricus I or Tetricus II you get. That is not something that would happen with Galba, apparently a more commonly available emperor than any of those.

If you want a ranking of emperors by how often they come up in the major auctions then you have that, but I don't see how it is of much use to be told a Tetricus II will be as hard to acquire as a Balbinus. You can buy a Tetricus II from one of the few hundred on eBay or the 168 on VCoins for as little as EUR10. There are 34 of Balbinus on VCoins, the cheapest being USD450.

There may also be a problem with what is being counted on Coryssa. I couldn't understand how Decentius comes out rarer than Valentinian III. But it might be to do with searching for names in the 'description'. So you have:

Valentinian III - 1,600 in the list; 1,626 results on Coryssa if include the 'description'; 300 if only the title. (This includes eBay).
Decentius - 1,566 in the list; 1,545 results on Coryssa if include the 'description'; 780 if only the title.

Why this difference? One reason is that the public auctions (unhelpfully) do not include the emperor's name in the title e.g.
Title: CNG EA 477 #669
Description: Valentinian III. AD 425-455. AV Solidus.

But another reason is that the descriptions mention other emperors in the histories of coins, and Valentinian III is written about more often than Decentius e.g.
Title: Nomos 20 #394
Description: Justa Grata Honoria, Augusta, circa 426-450. Solidus.
Honoria was the older sister of Valentinian III..."

So if the results are based on the descriptions, which they have to be, they might be including coins that are not of the emperor named.

[rasiel]

Well, I agree with you up to a point. The only thing I lay any claim to is coming up with a systematic way of tracking the relative rarity through gauging single lots sold at auctions. I can't tell how loosely or tightly it correlates to the wider market when this includes includes private sales, fixed price lists and, especially, group lot sales. No doubt that that would skew the results but it's not something that can be measured accurately. It is also, hopefully, not very relevant since group lot auctions tend to fall into either the dregs not worth cataloguing individually or those meant for resale individually; in which case they eventually go on to be caught in the dragnet so to speak. The bulk of my work in numismatics is geared around developing tools with "real world" application. Abstract data is of course of great interest but it's often stuff that I can't really sink my teeth into; I end up being just another guy with an opinion - not terribly useful.

Another significant way in which market and absolute rarities differ is that the former makes no effort to weed out repeat sales. In fact, you would not want to do this. To use the most extreme case, if there was just a single Silbannacus but its owners repeatedly bought and sold it you could make the argument that it's not rare to find a Silbannacus as "they" were frequently available for sale during the period the analysis covered. This of course tends to distort the market at the opposite end of the scale. This isn't just theoretical happenstance. It does happen frequently and has an outsize influence on making rare rulers appear more abundant than they actually are. To use a personal example* I can take the case of portrait coins of Artavasdus, one of the keys for the Byzantime series. Just 18 sales from 1932 through 2020, a figure that belies its true rarity when you examine the list more carefully to see that three of them account for a third of the sales!

The second part you pointed out is, thankfully, one where I have a much better grip on. The list is not compiled either by title or description - which would introduce many, many errors -  but rather by predefined categories. To take your example, if you do a global search on "Valentinian III" right now you get a total of 1,919 hits. But, as you noted, this is a very inaccurate value because many records will have this in their descriptions when selling, say, a coin of Honorius. In the above link this text string for some reason even figures in coins of Indian staters(!). A better method, one which yields fewer but better results, is to not do a search at all but simply pre-select the Roman Imperial period, which should immediately cut out Indian coinage, then select the All Auctions link (to omit private sales, etc.). If you click on this link you now see we have a Valentinian III link with just 1,585 records. If you were to go into those you'd hopefully not run across too many coins that don't belong to this reign. The 15-record difference between the count today and the list represents the net result of records added and taken out since the list was done a few days ago. It's always a moving target because of this but one that is always more refined and which largely keeps the positional integrity because the data is always being pruned at random rather than sequentially.

Hope this clarifies things a bit. Happy to give more details as needed!

Rasiel
* My Artavasdus, from a recent CNG sale. Rarer than polls suggest ;- )