Dies and Die Study Results - Greek Bronze

[PtolemAE]

I'm new to the process and would like to learn from others what one is apt to expect in die study results.

RE. ancient Greek bronze coinage -

Are there typically more obverse dies for a particular type than reverse dies?  or vice versa?

I think I recall learning that one ought expect to find a surplus of reverse dies due to the nature of coin striking technology for ancient Greek material but I don't recall if that is correct or why that might be so (or if perhaps the opposite should be expected) or if that would apply only to silver coins or ...

Knowledgeable comments and references would be helpful.

Thanks,

PtolemAE

[Lloyd Taylor]

On this thread https://www.forumancientcoins.com/board/index.php?topic=68444.0 the following observations in answer to a question regarding coins per die:

10,000-30,000 per obverse (anvil) die is the range most studies come up with for tetradrachm dies;  a figure of 25,000 being the oft quoted figure in econometric studies of ancient economies (e.g. Aperghis - The Seleukid Royal Economy) which tie a die count to known volume/weight (talents) coined as recorded in the historical record for some specific mints/coinages/times.

Reverse (punch) dies receiving directly the hammer blow only lasted for a third, or less, the number of strikings.  This latter point is confirmed by numerous ancient die studies where the usual average is around three reverse dies per obverse die.


This said in the context of Greek silver, but the forces and dynamics involved are no different when it comes to striking bronze so relativities of die life obverse vs reverse could be expected to be similar.

Some readily accessible references (again mostly silver coinage as die studies seem to be rarely documented/conducted on common bronze emissions):

Newell in ESM and WSM makes many observations and notes regarding die studies of Seleukid types.
Kritt The Early Seleucid Mint at Susa illustrates the die study process and its relevance with respect to the output of Susa under Seleukos.
Houghton Some Alexander Coinages  of Seleukos I with Anchors in Mediterranean Archaeology Vol 4, 1991 contains a die study of a specific group of emissions thought to be from Arados and Marathus by Newell.  Die studies proved instrumental in the reassignment of these emissions ultimately to Babylonia  (Babylon II and Uncertain Mint 6A of Houghton and Lorber Seleucid Coins) via an intermediate step documented in Houghton Aradus, not Marathus in Studies in Greek Numismatics in memory of Martin Jessop Price eds. Ashton and Hurter 1998.

For a corpus and die study involving bronze emissions of Hermione refer to Grandjean, Catherine. Le Monnayage d’argent et de bronze d’Hermione, Argolide.  Revue Numismatique, Annee 1990, Volume 6, Numero 32. The BCD Peloponnesos catalogue (LHS Numismatics The Coins of the Peloponnesos: The BCD Collection. Auction Catalogue LHS 96, 8-9 May 2006) also makes many a reference to bronze die studies in the emissions of the Peloponnesos.

Plenty more such studies are available.  I have only listed those that are currently accessible on my desk.

[cicerokid]

Originally and still significantly die studies are the backbone of the internal sequencing of the Athenian New Style  tetradrachms typified by Thompson, M "The New Style Silver coinage of Athens" ANS 1961

Since the obverse lasts much longer than the reverses some obverses  lasted so long that they were used on totally different reverse types thus linking the two .

In the 1970's the re-ordering of the mid 120's  reverse types of the New Style tetradrachm  had been postulated and now confirmed by a obverse die link commonality. ( Meadows, A.  " Thasos"/ New Style Hoard 1996 (CH9.265).)

Cicerokid

[PtolemAE]

On this thread https://www.forumancientcoins.com/board/index.php?topic=68444.0 the following observations in answer to a question regarding coins per die:

10,000-30,000 per obverse (anvil) die is the range most studies come up with for tetradrachm dies;  a figure of 25,000 being the oft quoted figure in econometric studies of ancient economies (e.g. Aperghis - The Seleukid Royal Economy) which tie a die count to known volume/weight (talents) coined as recorded in the historical record for some specific mints/coinages/times.

Reverse (punch) dies receiving directly the hammer blow only lasted for a third, or less, the number of strikings.  This latter point is confirmed by numerous ancient die studies where the usual average is around three reverse dies per obverse die.


This said in the context of Greek silver, but the forces and dynamics involved are no different when it comes to striking bronze so relativities of die life obverse vs reverse could be expected to be similar.

Some readily accessible references (again mostly silver coinage as die studies seem to be rarely documented/conducted on common bronze emissions):

Newell in ESM and WSM makes many observations and notes regarding die studies of Seleukid types.
Kritt The Early Seleucid Mint at Susa illustrates the die study process and its relevance with respect to the output of Susa under Seleukos.
Houghton Some Alexander Coinages  of Seleukos I with Anchors in Mediterranean Archaeology Vol 4, 1991 contains a die study of a specific group of emissions thought to be from Arados and Marathus by Newell.  Die studies proved instrumental in the reassignment of these emissions ultimately to Babylonia  (Babylon II and Uncertain Mint 6A of Houghton and Lorber Seleucid Coins) via an intermediate step documented in Houghton Aradus, not Marathus in Studies in Greek Numismatics in memory of Martin Jessop Price eds. Ashton and Hurter 1998.

For a corpus and die study involving bronze emissions of Hermione refer to Grandjean, Catherine. Le Monnayage d’argent et de bronze d’Hermione, Argolide.  Revue Numismatique, Annee 1990, Volume 6, Numero 32. The BCD Peloponnesos catalogue (LHS Numismatics The Coins of the Peloponnesos: The BCD Collection. Auction Catalogue LHS 96, 8-9 May 2006) also makes many a reference to bronze die studies in the emissions of the Peloponnesos.

Plenty more such studies are available.  I have only listed those that are currently accessible on my desk.

Having come upon a curious result in some recent work I'd be most interested in the ratio of obverse to reverse dies found in the bronze coin die studies and whether those are 'fixed' die axis types or 'variable' die axis types.  I don't have those books (the one on Hermione nor the LHS Peloponnesos catalog).

Tks,

PtolemAE

[Lloyd Taylor]

The coinage of Hermione was minted over about 100 years from the mid fourth to mid third centuries BC. Surviving bronze coinage in the corpus of Grandjean amounted to 230 coins in chalkous, or dichalkon, denominations. Diameter is typically in the range 12-16 mm and they were struck with adjusted dies to 12h, although minor variability 11h - 1h is apparent . In bronze 135 obverse dies and 149 reverse dies are recorded by Grandjean with a maximum recorded association of 4 reverses with one obverse. 

One caution: I think that Grandjean may have overstated the die count by mistaking die wear and breaks for new dies and even coin wear for such.  This is apparent in a number of examples and is the subject of comment by BCD in the LHS catalog: "It is a pity that there are so many mistakes and inaccuracies in the [Grandjean] die study since this detracts from the the pleasure of trying to build a comprehensive series for the mint."

As a general observation, die studies in bronze tend to be more problematic than silver due to the effects of wear and corrosion making mapping of unique points of concurrence more difficult than is usually the case in precious metal which tends to be better preserved (for a number of reasons).  Building a statistically valid database of reasonable quality bronze coinage, suitable for die study, of any emission can be an insurmountable hurdle in many cases.

[Lloyd Taylor]

On the subject of relative die life of a hinged (i.e. adjusted reverse die) versus floating (i.e. unadjusted) die mount I have not seen any reference.  However, the case can be made that a hinged die would be subject to greater consistently repetitive stress during its life and thus subject to earlier failure than the floating variety which would be struck at various orientations during its life. Stress exploits original metal/structural weakness in the die and consistency of stress over life is likely to accelerate failure via the original weaknesses in the die.  Some might argue that the extra support for the die implicit in a hinged mount might more than offset the effect of consistent repetitive hammer blows, but I have reservations on this as any keyed hinged mount mount needs to be loose enough to permit easy and efficient die changes and constructed in a manner that enables it to sustain the repetitive hammer blows, which means most of the hammer blow force must be taken by the die held in the hinged mount, rather than the mount itself.

[curtislclay]

I'd say it's no hard task to produce a perfectly reliable die catalogue of ancient bronze coins, once you have learned to distinguish details deriving from the die from later tooling or damage or mere lighting effects in a particular image. Just because a number of incompetent scholars have made a mess of the task, doesn't mean it can't also be done well! Examples: Kraay's die catalogue of Galban and early Flavian sestertii; Mildenberg's die catalogue of Bar Kokhba bronze coins.

[Lloyd Taylor]

I'd say it's no hard task to produce a perfectly reliable die catalogue of ancient bronze coins, once you have learned to distinguish details deriving from the die from later tooling or damage or mere lighting effects in a particular image. Just because a number of incompetent scholars have made a mess of the task, doesn't mean it can't also be done well! Examples: Kraay's die catalogue of Galban and early Flavian sestertii; Mildenberg's catalogue of Bar Kokhba bronze coins.

I'd agree within the context of Imperial Roman bronze which was struck in much larger volumes than most Greek emissions and half a millennium later. Roman coin hoards tend to contain much larger amounts of bronze that Greek hoards which also provides a fertile source of well preserved material for study. As a result, I think Greek bronze and Roman bronze pose distinctly different problems in terms of assembly of appropriate study material.  This is aside from the competence or otherwise of the scholars in these respective areas, which I would dare not debate!

[Aarmale]

You could use the Menorah Coin Project (http://menorahcoinproject.org/) as a helper for your die study.
Fontanille uses and interesting technique that I am learning for making composites.
Many images poor examples of coins from a single die, and are put together to form what the die would have looked like.

I have a small online die study that I made (http://judaea.chimehost.net/main/study/), but is is very small (about 50 coins in total).

[curtislclay]

Greek bronze coins are no less susceptible to accurate die cataloguing than Roman bronze coins, in my opinion.

A problem that affects both fields is assembling enough material to produce die links and hence advance our knowledge, which is of course the goal. About fifty years ago Sutherland attempted a die study of the moneyers' aes of Augustus but had to give up because his sample of several hundred pieces produced virtually no die links!

I would say you are perfectly justified in calling the author of a die catalogue incompetent for the task, if every plate of his published study demonstrates that he was unable to recognize die identities!

[Lloyd Taylor]

I would say you are perfectly justified in calling the author of a die catalogue incompetent for the task, if every plate of his published study demonstrates that he was unable to recognize die identities!

A lady in this case.... Catherine Grand Jean.

Sure there are deficiencies in the die study, but the catalog still remains the most comprehensive corpus of the small coinage emitted from Hermione.  More so if one is aware of its limitations, particularly in respect of die identifications. 

I am unaware of the background under which Grand Jean worked and whether the deficiencies can be excused by way of work pressure, deadlines etc, access to material, etc., or whether it reflects incompetence.  In any event, it is not my role to be judgmental, rather I prefer to let the facts/coins speak for themselves. One could attempt to recast the study based on images and results, but this is prone to equally large error in the absence of all coins being plated. Moreover, the inaccuracies appear to be roughly equally reflected in the obverse and reverse die ids so that relativity of obverse to reverse dies remains as specified, although the absolute qatum in each case is in error. The original question posed was regarding relative die lives so that the observations of Grand Jean are still relevant to the matter although the absolute die counts may be in error.

The reason I placed this reference before PtolemAE (with the appropriate caution) was that it was the only one I had to hand, without a search of my library, that reflected upon his original inquiry regarding Greek Bronze die studies.  As he asked, "I'm new to the process and would like to learn from others what one is apt to expect in die study results".  In this case, Grand Jean's Hermione study is an example, perhaps with the bar set at the low end, of what to expect.  But it was never posited as anything other than an example of a die study with all the inherent limitations,uncertainties and interpretation outcomes that accord to any such study.

In the final analysis, all die studies are subject to a greater or lesser degree of uncertainty, dependent on a host of factors including such as the quality of the material under study and the diligence and/or competence of the scholar undertaking the study.  With worn bronze material the assessment can be quite subjective and that remains a fact of life.

[PtolemAE]

I would say you are perfectly justified in calling the author of a die catalogue incompetent for the task, if every plate of his published study demonstrates that he was unable to recognize die identities!

A lady in this case.... Catherine Grand Jean.

Sure there are deficiencies in the die study, but the catalog still remains the most comprehensive corpus of the small coinage emitted from Hermione.  More so if one is aware of its limitations, particularly in respect of die identifications. 

I am unaware of the background under which Grand Jean worked ...

Thank you and Curtis for very helpful references and comments.

In our study we tried to be cautious and put two pairs of eyes on the coins, rejecting poor photos or coins worn badly or damaged (about 20-30% were unusable for die comparisons).  I hope we didn't miss matches but there are plenty of intricate design features that permit the dies to be compared when the photos are good enough.  We also worked mostly from large high-res digital color photos so we could compare side-by-side on a PC display.  It's extremely tedious but we tried very hard to do it right, being neither overly optimistic in favor of matches nor carelessly rejecting them.

Still not as large a sample as I'd like and it took years to obtain all the photos to have enough (I guess we would never have too many to get some sample size statistical confidence.  Just kept at it, scouring wherever we could, and several people were very generous with private and museum collection photos.  Even took high-res photos of some normal size book plates.  Online archives from auctions were also valuable.   This work is for publication and we think it will make a nice contribution of some unexpected, but now well-supported, implications for ancient numismatics.   Maybe some surprises in die count estimates, ratios of reverse:obverse dies, etc. in light of comments I've read in this thread.

PtolemAE

[Lloyd Taylor]

In our study we tried to be cautious and put two pairs of eyes on the coins, rejecting poor photos or coins worn badly or damaged (about 20-30% were unusable for die comparisons)....

I think you highlight an important point when considering Grandjean's work.  She compiled a corpus and then established a die count using every individual known example regardless of state of preservation. This approach is fraught with problems as evident in her die count, but she had a limited database of extant coins to begin with, from a small mint that probably only operated intermittently for a few decades.  A corpus should not dictate the requirement that every known coin be matched to a die pair, unless the state of preservation of each coin is appropriate to do so with some confidence.

The approach you have taken to discard from analysis those coins in an inappropriate state of preservation for confident die matching is the correct way to go. 

By the way, the thought occurs to me that with the very large diameter Ptolemaic bronzes you could/would get a different answer due to the greater mass of the die and the different relief of the design relative to small diameter bronze coins.  More metal and lower relief in the die would enable the die to absorb greater shock loads for a longer period than the smaller dies...thus different die life and perhaps (even probably) a different ratio of reverse to obverse dies. Remember for a constant hammer blow/load on the reverse die, the face load/stress on the die decreases with the square of the radius of the die.... this might explain some of what I infer you are observing in the Ptolemaic bronze die count.

[PtolemAE]

On this thread https://www.forumancientcoins.com/board/index.php?topic=68444.0 the following observations in answer to a question regarding coins per die:

10,000-30,000 per obverse (anvil) die is the range most studies come up with for tetradrachm dies;  a figure of 25,000 being the oft quoted figure in econometric studies of ancient economies (e.g. Aperghis - The Seleukid Royal Economy) which tie a die count to known volume/weight (talents) coined as recorded in the historical record for some specific mints/coinages/times.

Reverse (punch) dies receiving directly the hammer blow only lasted for a third, or less, the number of strikings.  This latter point is confirmed by numerous ancient die studies where the usual average is around three reverse dies per obverse die.


...

Interesting suggestion of 3:1 ratio (reverse:obverse).  Studies of some silver coins of Syracuse show a range of about 2:1 to as low as nearly 1:1 -

http://bmcr.brynmawr.edu/2002/2002-08-05.html

One wonders about the technological differences of coin manufacture leading to these findings.

PtolemAE

[Lloyd Taylor]

...One wonders about the technological differences of coin manufacture leading to these findings.

To be honest, its not something to which I'd given much thought until you raised it here. But most analysis I have read and quoted is based on Hellenistic tetradrachm die studies.  Most commonly coinages with adjusted dies.  I had assumed (unthinkingly) that the resultant statistics would be applicable across a wide range of coin manufacture.  However, thinking about it this is not the case. 

Die material, die size, die volume, die mounting (e.g. hinged adjusted vs floating/unadjusted), engraved relief, even engraved typology and hammer size (instantaneous loading) will all play a significant role in determining die life. The old basic school physics come into play: F=ma and P=F/a ( all impacted by diameter relief and design typology), plus consideration the structural strength and homogeneity (or otherwise) of the die material.  Certainly refining of metals improved over the first millennium of coinage, so that die life conclusions are at best time and culture specific. Interesting indeed!

[PtolemAE]

...One wonders about the technological differences of coin manufacture leading to these findings.

To be honest, its not something to which I'd given much thought until you raised it here. But most analysis I have read and quoted is based on Hellenistic tetradrachm die studies.  Most commonly coinages with adjusted dies.  I had assumed (unthinkingly) that the resultant statistics would be applicable across a wide range of coin manufacture.  However, thinking about it this is not the case. 

Die material, die size, die volume, die mounting (e.g. hinged adjusted vs floating/unadjusted), engraved relief, even engraved typology and hammer size (instantaneous loading) will all play a significant role in determining die life. The old basic school physics come into play: F=ma and P=F/a ( all impacted by diameter relief and design typology), plus consideration the structural strength and homogeneity (or otherwise) of the die material.  Certainly refining of metals improved over the first millennium of coinage, so that die life conclusions are at best time and culture specific. Interesting indeed!

I hadn't given it much thought, either.  It just  jumped out at me from our data, among other differences and some features shared in common.  It just popped out as something we hadn't noticed and seemed quite at odds with the results I've seen reported for other coin types.

FYI, the coins we are studying that yielded this curious result are not the giant 40+ mm Ptolemaic bronzes.  This is a continuation of the investigation that was started about 3 years ago into early 3rd C. bronze diobols, the first part of which was published on the www.ptolemybronze.com web site some time ago.  The coins are about 27mm and their relief is not especially noteworthy one way or the other; but a lot of other things about these coins are quite interesting indeed.

Thanks for your comments and references.

PtolemAE

[El Reye]

As Lloyd points out there are many variables to consider in the life span of a die, and I am sure that the advances in metallurgy played a role. Take a look at these examples from Teos @ 500 BC, and the description provided by CNG.

“Balcer group I (unlisted dies). VF, a few die breaks. Three (3) coins in lot, all struck from the same dies (both unrecorded by Balcer), but at different states of die deterioration.”
“Judging from these examples, it appears that the deterioration of this obverse die began almost immediately, and progressed rapidly. The resulting limited output would explain why there were no examples of it for Balcer to record. A survey of other examples suggests that this rapid deterioration was not an uncommon phenomenon in the early period of minting at Teos. It is possible that these early dies were made from metal that was not suitable for the purpose of striking coins. By the early Classical period, though, this problem appears to have been rectified. “


With this rapid die deterioration I would be surprised if more than a few thousand or so were produced with these dies. My guess is that by Classical times these metallurgy problems were rectified and dies were routinely producing coins in the tens of thousands.

Cameron

[Lloyd Taylor]

....With this rapid die deterioration I would be surprised if more than a few thousand or so were produced with these dies. My guess is that by Classical times these metallurgy problems were rectified and dies were routinely producing coins in the tens of thousands.

A very nice example which in this case shows the obverse (anvil) die breaking up more rapidly that the reverse punch (note the deterioration between first and second right quadrants of the reverse that is apparent between the first and third coins).  In this case the obverse die life would likely be shorter than the reverse punch life.