An unusually thin and lightweight Henry III penny is described; the authors are hoping to receive reader suggestions as to what this coin may represent.
Henry III – Long Cross Penny – A Challenging Piece – A striker’s foible or just an undetected error? – Ian M. Heavisides and Robert Page
BNS Research Blog 
Could it be a contemporary forgery?
The idea is an interesting one but the dies of Bury were issued sequentially, and this being Eaglen Dies Qq and the only die to have a triple colon, we have been able to compare it with a full weight version from the same. Using the letter shapes and their position relative to both each other and the inner rings of pellets, both obverse and reverse, the coins proved to have come from identical dies. Similar dies do exist for Nicole on London, ie Class 3d2 with a colon in the legend and it is just possible that dies were tested on creation in London, possibly on scrap although this still doesn’t explain how an underweight coin found its way into circulation.
David Greenhalgh – asked a question on a Facebook forum….
Interesting article, minor point it appears to read that the Henry III double penny is a unique piece when there are at least 3 examples struck by 3 different moneyers William de Gloucester, Gilbert De Bonnington and Robert De Cantuaria, admittedly each moneyer is represented by only a single specimen of coin.
Having received a response other than through this blog, asking if we were aware of two other two pence pieces existing, one for Robert and one for Gilbert, we decided to publish our response here.
Yes well sort of, your point is taken, but in this case the dies, both obverse and reverse appear to be unique.
The obverse is not that of Gilbert nor, if the drawing is correct of Robert (pp 23-25 in Mints and Moneyers During the Reign of Henry III – Ron Churchill – Baldwins 2012).
Contrary to Coincrafts statement that, “nothing else aside from its weight and slightly larger diameter would have distinguished it from an ordinary penny during the era.”, the legend is unique in beginning h EN RICVS ie EN ligated whereas it is the N & R that are normally so treated and as they appear on the Robert and Gilbert coins. This rather deepens the mystery as to why, if there were only a few coins struck, more than one obverse was used.
Finally just for the sake of precision and greater mystery, Robert of Cantuaria’s die passed to William of Gloucester on 1st October 1257. If these coins are in the style of Class 5g they would have had to be produced before the general production of 5g began for Robert of Cantuaria to be the moneyer. However the letter X appears to be of a type more commonly associated with 5h – Type 4c, (our numbering as yet unpublished), in which case Robert was Robert Wylof/Weterlock (Churchill p.127).
Due to its light weight, and having regard to the photograph, is it possible that this example is a cast coin?
Thank you; that comment certainly sent us back to look at the coin again and to compare it with one from the same dies which fortunately is B661, the actual coin illustrated in Eaglen’s book.
Under the microscope both sides of the coin are pitted uniformly on the surface but the lettering and detail is very sharp edged and quite deep. If this is a cast then the mould would have had to be taken from a coin made very early in the use of the die. The Eaglen coin shows a loss of sharp detail as the dies wore and letters flattened slightly but both coins show some variation in the thickness of the flan which you would expect from hand beaten flans.
In fairness we can’t discount your idea totally but would ask whether it is feasibly possible to cast a coin using such a slight depth and wouldn’t it be more practical to use a deeper mould and a greater amount of base metal?
If anyone has further ideas on the above, a practical way of testing the coin, or a copy of Eaglen 286 Dies Qq that has sharp edged detail we would be delighted to hear from you.
The coin is so obviously thin and lightweight that it cannot conceivably have been struck with intention to deceive.It was possibly struck as a practice piece by an apprentice hammerman, using regular dies and an economically light flans It may then have been mistakenly included in a batch of coins officially issued by the mint..
An intriguing notion and one that can not be dismissed easily. I believe that there is an interesting story behind this and wonder whether anyone else has any coins of a similar weight that might help support such a theory? I suspect that, whether the striker was in Bury or perhaps in London trying out the dies before dispatch, the coin did not go through the official method of entry into circulation which surely would have involved weighing.
If the mint made an issue by tale the lightness of an individual coin would be masked.
Yes, good point, and after consideration we believe your suggestion as being the most likely. Many thanks for your input.