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  • Writer's pictureMatilda Siebrecht

"I know what it is!" - discussing the mystery of the Gallo-Roman Dodecahedra

So after saying in my last post that I was going to focus on mugs, makes, and microwear, I've decided to expand out to cover a particular mystery object that has been causing some consternation! (Hey, it still begins with an 'M'!)

Those of you who have joined this blog from the Instagram page of The Archaeologist's Teacup may remember my weekly #TeaDay reels, in which I spent one minute introducing a very brief summary of some kind of ancient object. These reels have now expanded out into my monthly podcast episodes, but the originals are still on Instagram, and are also in a playlist of shorts on the YouTube channel. One of these videos is on the Gallo-Roman Dodecahedra, and the wave of comments on it over time has inspired my to write this blog post. Here is the link to the video:

What are the facts?

The first recorded description of these objects was in 1739 when a Mr North presented to the Society of Antiquities in London "a piece of mixed metal, or ancient brass, consisting of 12 equal sides". Since then, there have been just over 100 of these found in total, which is in itself an interesting point to consider, and something I'll come back to below. They are generally dated to between the 2nd-4th centuries AD, and are found in a relatively wide geographic range between modern-day England and Hungary, but they are particularly concentrated in that region known by the Romans as Gaul - hence the name "Gallo-Roman Dodecahedra".

When looking at things claiming to be "mystery objects" it is always important to look at the context - i.e. the kind of site or archaeological feature that they are found in. For example, if something is always found in the same kind of site, then it might not be quite so mysterious after all. However, most of those objects of unknown use come from a wide range of sites, and the dodecahedra are no exception. They have been found in Roman military camps, public baths, temples, theatres, and tombs. So no particularly clear pattern that can associate them easily with a particular purpose!

So let's hear the theories

"As to the intended purpose of these objects, nearly fifty different theories have been published in the scientific literature; some of them brilliant, some fantastic, and some downright absurd" (Guggenberger 2013, 59).

This was such a perfect quote that I couldn't resist sharing it, because all of those categories have so far been included in the comments of my original short video. Let's start with the most polite and practical of the suggestions given.

Remember I mentioned the relatively low number of these objects that have been found? If it was a commonly used tool, as many theorists have suggested, one might assume that we would have found more of them. After all, Roman objects are usually pretty plentiful. And they are mainly made from bronze, which while easily corrodible, does still survive in the archaeological record, as shown by the wide variety of other bronze items that we have from this time period. Nevertheless, it may of course be that these objects are indeed a simple tool of some kind, although what kind of tool is still a matter of some debate. Also, remember the wide range of sites that they have been found in? Why would you need a shoe-making tool in a bath?

Candlestick holder is a popular suggestion, mainly due to the fact that a few dodecahedra were discovered with some wax residue attached to them. It is indeed a nice idea, and they probably look very pretty as a candlestick holder. However, this may also be the classic situation where modern perceptions of what something should be are immediately put onto objects from the past, without really considering the (pre)historic context. I'm not saying they're definitely not candlestick holders, but personally I feel like that's giving a lot of artistic license.

Another suggested use is as some kind of wayfinder - by looking through different holes in order to measure distance based on mathematical formulas. There were some interesting and very mathematically charged reports on this written by Amelia Caroline Sparavigna from the Department of Applied Science and Technology in Torino, Italy. However, as the author mainly cited Wikipedia as her main source for information (with some special appearances of Fox News), and apparently didn't actually handle or analyse the objects herself, I am taking these reports with a slight pinch of salt... Of course, you don't need to have a fancy peer reviewed and institution-affiliated paper to back up your claims in order to be taken seriously, but you need to at least be able to provide some relatively solid evidence that you have conducted viable research in some way.

The issue with the other suggestions is that, although several similar Dodecahedra have been found, no two objects are identical. If they were used as some kind of tool for standardisation, such as in shoe-making, checking for counterfeit coins, or cordage making, then you would assume that the tools themselves should also be standard. But if you look at images of the range of different pieces - for example those in the chapter by Tibor Grüll (2016) - they all look very different in terms of both shape and size.

Next we have some fun suggestions - they were puzzles or game pieces of some kind. This is a lovely idea, and I definitely want to try some of the theories out at some point with my own replica, but the main issue raised here by most archaeologists and historians is that there is no written record of these objects. If they were involved in some kind of game, you would imagine that somewhere we would have read a reference to them, or else would see it depicted somewhere in surviving Roman art. But the fact that there is no mention of them anywhere makes all of the ideas - but especially those related to gaming - a little more tentative.

Ah the wonderful friendly community that is the internet... Of course people will watch these videos - even a one minute short - and apparently completely miss the majority of what has been said and immediately attack. As you may have noticed if you watched the video, I did in fact say that their use as a knitting tool is one of the most popular theories. However, that is indeed all it is; a theory. I particular like the use of capitalisation for the word "exactly" in the second comment. As we have seen, according to other people they are also still in use today for various other purposes, so they also claim to know "exactly" what they are.

The main support for the theory that they are used as knitting tools comes from some fun experiments done with replicas (watch an example here), which shows that indeed they can be used to knit. However, I can also use a screwdriver to stir my tea, but that doesn't mean it's the intended use of it. Again, I'm not saying they're definitely not a knitting tool, but it's impossible to ever know exactly how something was used in the past. The only thing archaeologists can do is make suggestions and theories based on evidence, otherwise the interpretation gets extremely biased.

And then of course YouTube wouldn't be YouTube without the input of the pseudo-scientists...

So how can we know?

Although several of the commenters seemed to think that I was making these objects out to be some kind of mystical and ritual object, that wasn't at all my intention. I was just trying to share what I believe to be a really fascinating type of object, and discuss some of the many theories surrounding its use. I also think it's important to showcase that there are still really interesting and exciting mysteries in archaeology, and they are not always related to some kind of treasure or world-changing issue. So much of archaeology is sensationalised, but in reality, the most exciting thing (in my opinion anyway) is to try and figure out the everyday use of beautiful little objects such as these.

And of course, I have to ask: What is your favourite theory? Comment below!


Unfortunately there were several papers on this topic that I was unable to access, as they were behind a paywall (ah the joys of open-access academic research...) but I have shared those references that were available.

Reports by Amelia Carolina Sparavigna (Department of Applied Science and Technology) as the potential use of Dodecahedra as wayfinders / dioptra

Paper by Michael Guggenberger (2013) summarising current research into Dodecahedra, published in The Mathematical Intelligencer. (not open access - message me if you'd like a pdf copy)

Chapter by Tibor Grüll (2016) summarising the theories regarding Dodecahedra, published in the book From Polites to Magos.

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