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World Coins – A History of the Netherlands Gold Ducat, Part 3: The Importance of Primary Research in Numismatics

By Dariusz F. Jasek …..
Link to Part 1 | Part 2

The idea of this article is not to discredit other authors or publications mentioned here. However, without pointing out certain examples it would be impossible to explain how important it is to do primary research in numismatics. Of course, some mistakes are inevitable in publications, especially in comprehensive books. During my primary research while writing Gold Ducats of The Netherlands, I became aware of numerous mistakes in both old and new publications. Some of the major examples of these mistakes are listed in this article.

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In the beginning of my research on gold ducats I looked for the existing literature on the subject. André Delmonte’s well-known book entitled Le Benelux D’Or and Albert Scheffers’ The Dutch Gold Ducat (1586-1986) were my first choices. Shortly afterwards I searched for more new and old books.

The more that I read, the more I noticed that there were inconsistencies and direct contradictions within the different books and it was rather obvious that somebody had to be wrong. Given that, I soon realized that doing my own primary research would be the only way I could find true answers to my questions.

Modern Books

Delmonte’s book had already been supplemented by the Dutch numismatists many times, in the form of articles published by some Dutch magazines. But I never found any corrections of the museum attributions given by Delmonte. While doing my research, I made sure to verify every reference to every coin listed as being in a given coin collection. Thus, I found some that could not be verified, e.g. some of the Gelderland ducats listed as being in the State Hermitage Museum Coin Cabinet, were not actually, and had never been, in the State Hermitage Coin Cabinet.

Delmonte also listed some fancy coin types, like the Nijmegen double ducat with St. Stephanus kneeling. This specific coin seems to have been completely misidentified and is instead a Nijmegen undated double ducat with St. Stephanus standing; because the only known specimen, which was supposed to be found in the Vienna Coin Cabinet, was in fact never there. The reference to the Vienna Collection was reported by Delmonte and then duplicated by other authors in their own works, but I received confirmation directly from the Kunsthistorisches Museum that this reference is incorrect.

The Nijmegen double ducat:

Nijmegen double ducat. Images courtesy Fritz Rudolf Künker GmbH

Fritz Rudolf Künker GmbH & Co. KG – Auction 197, Lot 6136

The only publication specifically about The Netherlands gold ducats–a red booklet published in 1986 by Albert Scheffers on the 400th anniversary of introducing this coin type–is a very good book. In the listing of dates when gold ducats were minted, however, Scheffers made a number of mistakes.

Looking further for modern Dutch books on the provincial coinage I found two of the leading coin catalogs in The Netherlands today: “Catalogus van de Nederlandse munten” by Jan C. van der Wis and Tom Passon, and a two-volume set entitled “Handboek van de Nederlandse Provinciale Muntslag” by Dick Purmer. Both are very good books on the subject, and of equal importance.

But sometimes they contradict each other. For example, when it comes to the Gelderland 1715 double ducat, according to one author (Purmer) it was supposed to have been minted with a mintmaster’s privy mark (a crane). Yet according to the other authors (Passon & van der Wis) it was minted without this privy mark.

Therefore, I contacted the Norwegian Museum in Oslo, where the only known example of this date can be found. Looking at the coin was the only way to judge which book description was correct. The coin has the privy mark.

The Gelderland 1715 double ducat:

Gelderland 1715 double ducat. Images courtesy Norwegian Museum

Museum of Cultural History, University of Oslo Norway

The Krause catalog series, a well-known series of books in the US, may also be inaccurate. When looking for the fineness of the Spanish “pistolet” (escudo), the standard followed by some of the Dutch mints, I found different numbers, depending on which Krause book I used.

The first escudo listed (1607-C) has the following metrics in Krause:

  • World Gold Coins – 3.3800gm, 0.901 gold;
  • Standard Catalog of World Coins: 1601-1700 – 3.4335gm, .9167 gold;
  • Spain, Portugal, and the New World – 3.3800gm, .9010 gold.

It’s impossible to pick which is the correct value.

Auction Catalogs

Auction catalogs are one of the most important sources in numismatic literature. Their importance is extremely high, but they have to be browsed by the researcher carefully. Time spent on verification of auction records pays off, because this way we may find incorrect information, which seems to be copied from one book to others without double-checking the sources (auction catalogs) referenced by the authors.

For example, the “Batenburg ducat with the date of 1579”, found in the Jacques Schulman auction 27 from 1896, is in fact a Transylvania ducat, not a Batenburg ducat. Wrong identification of this coin, given by Jacques Schulman in his auction catalog, resulted in it being listed by other authors as a Batenburg ducat.

This non-existant 1579 Batenburg ducat was listed by several authors including Delmonte (Le Benelux D’Or), Friedberg (Gold Coins of the World: From Ancient Times to the Present), Pannekeet (Catalogus Gelderse steden en heerlijkheden) and Purmer (Handboek van de Nederlandse Provinciale Muntslag 1568-1795. Deel II). How did I find this mistake? By following the source cited. In other words, I needed to take the original catalog into hand and see if it’s listed correctly.

I was lucky because this extremely rare catalog was accessible in the library of Teylers Museum and I was allowed to work with it.

Secondly, although it’s a catalog printed in 1896, it has plates of a few selected coins (a rare addition in auction catalogs at that time) – including the coins I was interested in. The picture in the catalog was very low quality, but after digital restoration I was able to read some details on the coin. What’s more, the legend of both sides is written in the catalog.

This coin is an excellent example of an instance where a collector has no chance to ever notice the mistake–it was actually incorrectly listed by all catalogs!

The Transylvania 1579 ducat:

Transylvania 1579 ducat, misidentified as Batenburg 1579. mages courtesy Ira & Larry Goldberg

Ira & Larry Goldberg Auction 41 (Ex: Dr. Terner Collection), May 30, 2007, Lot 4160

Speaking of auction catalogs, in the catalog of G. Theod. Bom from November 7, 1848, the sale of the famous collection of Hendrik Westhoff, I found the 1753 Zeeland gold ducat listed as being countermarked “with the ‘Gáfa’ word written with Arabic letters”. In fact, the word ‘Gáfa’ can be written in two different ways in Arabic, and one way of writing it is very similar to the word for ‘Java’. Therefore, the countermark on this ducat is probably nothing more than a misreading of Java. There are several known examples of this date that do have the ‘Java’ countermark. But none that have a ‘Gafa” countermark.

Shortly before completing the first volume of my book I found references to the 1664 Gronsveld ducat. The only copy of this coin was supposed to have been sold by Sotheby’s in auction 520. I managed to buy this rare catalogue only to verify if this information was correct. It turned out to be a good idea. The coin was incorrectly identified by the auctioneer; in fact, it was a 1642 Gronsveld ducat, the small date type.

It is absolutely worth paying attention to old auction catalogs, because many unique dates are only listed in these early auctions and never appeared in auctions again. In such early catalogs, plates with coin photos are very rare and thus we must be careful reading coin descriptions because we have no opportunity to verify if they are correct. But we may get lucky, like with the 1579 Batenburg ducat mentioned above, because a photo of this coin was found in the auction catalog from 1896!

Sometimes it’s also relatively easy to verify a coin’s description, e.g. when the coin is listed as a double ducat klippe with a weight of 7gm, it is an obvious mistake – a coin of this weight is a single ducat klippe.

Old Books

References to old books, like those of Verkade, van de Chijs or Serrure are usually quoted in the bibliography of books on coins from The Netherlands. Some of the coins pictured in drawings were contributed to museums or sold in auctions. Fortunately, I found some of them and compared these drawings with a photo of the real coin (the same specimen that was drawn). This way we may see how inaccurate the details in the coin’s drawings were. Sometimes drawings of the same coin type are also different in details when compared to a drawing of the same coin type in two different books.

Information Online

Information online is important, but it must be used wisely. In the very beginning of my research I was looking for Dutch gold ducats over the internet. Now I see how limited this information is, and I was surprised by how often it is incorrect. Of course, there are exceptions, like sales archives of reputable auction houses, or records in well-known general numismatic archives, such as CoinArchives or NumisBids.

To correct some major facts about the Netherlands ducat, I created the website goldducats.com and wrote several articles which may be found there. And there are other articles on CoinWeek [See links at the top of the page. —CW].

However, I must say that the amount of incorrect information I found online is significant.


To judge and fix all mistakes for your research you need to double check everything. Ask museums for coin photos, compare them, and analyze. There are no shortcuts. In the end, if and when you have any doubts it must be written down, to let other researchers know your thoughts and opinions regarding every detail. High-quality photos of coins should be published when available to let your readers read the details not only in the description, but also on the coin itself.

When something is unclear, incorrect or questionable – you need to say it. Mark this coin as uncertain, state your reason and explain this reason. And most of all, you need to do everything you can to see the coins in hand, or at least good quality photos of them. It may cost a lot of time, effort and money, but that’s the only way.

In the beginning of my research my notes were full of gaps, questions and doubts. They required step-by-step verification for literally each date and mint. Thanks to my primary research I could face and answer many of my previous questions. However, co-operation with museums and good access to literature was crucial for making the research complete.

All of that explains the importance, the necessity, of primary research.

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Mr. Jasek’s most recent book, Gold Ducats of the Netherlands, won the 2016 Numismatic Literary Guild (NLG) award for Best Specialized Book on World Coins. Be sure to visit his website at www.goldducats.com.

Coinweek is the top independent online media source for rare coin and currency news, with analysis and information contributed by leading experts across the numismatic spectrum.

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