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The Roman Gadget Archaeologists Can’t Figure Out

Written by Laura Davies

Almost 300 years ago, in 1739, archaeologists in England uncovered a Roman device that completely baffled them, and everyone since. A bronze dodecahedron, unlike anything anyone had found before. Since then, more than 100 have been uncovered. Many puzzle solvers have tried to hypothesise their intended use and the guesses range from military applications to an elaborate Roman brothel pricing system, based on girth. Whether a larger measurement would lead to a price hike or discount, I’ll leave up to you.

The presence of wax in 2 specimens indicated that they were candleholders, but that’s since been explained as a remnant of the lost wax casting process. In fact, pretty much every theory that’s been proposed has been written off, leaving a tantalizing mystery. For someone who’d like their name to go down in history for cracking the 300-year-old problem of the range finder, pebble measurer, star sign interpreter, or penis measuring device, it’s time to get to work.

The Dodecahedrons


The dodecahedrons themselves are intricate devices made of metal and sometimes stone. No two found have been the same and they vary in size from 4 to 11 centimetres. They’re all hollow and have 12 pentagonal faces with a differently sized circular hole in the centre of each, ranging from 6 to 40mm in diameter. Some have minor amounts of engraving as decoration and all have a small metal knob attached to each of its vertices. All dodecahedrons that have been dated were manufactured between the 2nd and 3rd century AD. This means they would’ve been expensive and taken great skill to make.


By far, the most common theory for their use is as glove knitting devices, like modern-day knitting dollies. Knitting wasn’t invented until 500 AD, at least 200 years after these devices were made. Therefore, it’s possible that the dodecahedrons were an early knitting method that just didn’t catch on. Probably as it’s incredibly fiddly and time-consuming.

Supporters of the theory often cite the locations of the dodecahedrons as proof that they were used for gloves. While they’ve been found in a variety of places, from Hungary to Wales, the largest concentration is in the northern corner of the Roman Empire, in Northern Gaul and Roman Germany. The colder regions of the Roman Empire, where they’d need gloves. Theorists also claim a glove maker explains the differently sized holes, as hands and fingers are different sizes.

The theory gained popularity due to crafters using 3D printed versions of the dodecahedrons to film themselves knitting the fingers of gloves, thus proving it works. Case closed.

Or is it?

Let’s start with the differently sized holes. When using the knitting dolly technique, the size of the knitted tube created isn’t affected by the size of the hole. It’s controlled by the number and spacing of the pegs. Therefore, there’d be no reason to have a complex device with 12 different hole sizes. The same thing could be achieved with just one hole and one set of pegs.

Secondly, despite the attempts of many who’ve uploaded their dodecahedron knitting tutorials to YouTube, no one has managed to use it to knit the palm. As knitting wasn’t invented for another 200 years, the glove couldn’t have been completed before the recipient was long dead. Essentially, it’s a device that could’ve been used to make five separate finger warmers. And it isn’t even very practical for making them. As the knitted tube forms inside the dodecahedron, it’d be incredibly difficult to judge the length until you’d completed each one.

Another issue with the theory is the fact that the majority of the dodecahedrons have been found at military sites. This poses two problems. Would the Roman army really have brought a team of knitters to the front with them, or would it have made more sense for them to be crafted at home and sent to the soldiers? Also, knitted gloves would be incredibly impractical in battle. Leather would’ve been much better for gripping a sword or accuracy with a bow.

Dodecahedron https://commons.wikimedia.org/wiki/File:Bronze_dodecahedron.jpg


Another theory that has gained traction due to the incredibly in-depth study done by its proposer, G. M C. Wagemans, is that they’re planting calendars. The idea is that the dodecahedrons can be used as an astronomic measuring instrument that uses the angle of the Sun to determine a specific date in Spring and another in Autumn. This would be useful in agriculture as farmers could ensure their Winter crops were planted at the optimum time to avoid frost.

However, no two dodecahedrons are exactly the same, putting a massive hole in the idea that they could be used as any kind of calibration or measuring instrument. Of the 2 devices trialled by Wagemans, there was a difference of 16 days. Another issue is that in order to work, the device must be completely symmetrical and stand perfectly horizontally. None of the dodecahedrons found were this perfect.

The military sites also cause an issue for this theory. Why would the majority of the dodecahedrons be found near the sites of battle and not of agriculture? Wagemans proposes that the troops would have had some responsibility for their own growing, but this doesn’t explain why the farmers didn’t own the majority of devices.

Finally, Julius Ceasar’s calendar came into effect on the 1st of January 45 BC. Surely, just asking for the date would’ve been an easier and more accurate method to use.


Theories of the dodecahedron’s use as a gauge don’t end with astronomical measurements. Some have suggested that they could’ve been used to measure coins and identify counterfeits. This idea was given weight by the discovery of the devices alongside two coin hoards. However, as none of the dodecahedrons have holes of the same size, it seems incredibly unlikely or they would’ve led to a huge number of counterfeiting arrests. 

Another gauge theory that actually takes into account the military sites, finally, suggests they were used as range finders for projectiles and ballistics. It was proposed by Italian physicist Amelia Sparavigna in 2012 and is highly plausible. The idea is that by aligning two of the holes, a user could look through the device and determine the distance to enemy troops. A vital measurement if you wanted to fire anything at them.

While critics cite the differently sized dodecahedrons as a problem, this wouldn’t necessarily be an issue with this theory. As long as the owner first used their device to measure a known distance, they could apply this to anything.

So that’s it then? A range finder?

Well, no. While it would technically work, it doesn’t explain all the knobs on the vertices. Why would the Romans waste time and money on the extra metal needed to decorate the dodecahedrons with them if they weren’t of any practical use? They just wouldn’t.

Another military theory is that they were used to gauge the size and roundness of ballista balls. We know the Roman’s cared about this as Vegetius, a writer of the 4th century AD, explained that river stones worked best as ballista as they were round, smooth and dense. Ballista stones have also been found at Masada, which were chiselled to make them as round as possible.

The theory is supported by the fact that 3 dodecahedrons have been recovered from rivers, suggesting that workers used to sit on the banks and use them as they carved. The different sized holes also make sense, as various diameters were required for varied distances and uses.

Seems plausible? Not really. Sure, it would work, but why create a complex dodecahedron when the same could be achieved by cutting holes in a flat piece of metal or even wood? Also, if the stone passed through the hole and into the centre of the device, it would be irritating to remove it, unlike with a flat device where the stone would pass straight through. And, of course, the decorative knobs are still an issue.

Many other military theories exist. It’s been suggested that they were used as the heads of maces, but they’re clearly too light, small, and decorative. Attempting to bludgeon someone to death with a hollow dodecahedron the size of an egg is likely to do more damage to the attacker than the victim.

There’s also been the suggestion that they were used as an ancient equivalent of police spike strips, being thrown on the floor to trip horses. But, if this was the case, you’d surely find 100 on one site rather than in total, and the Roman’s would’ve had to employ hundreds of metalworkers to produce enough to bring down just a couple of horses.

All the military theories are also weakened by the sites of some of the other dodecahedrons. While it’s true that most were found in militarized areas, 3 were found in graves, including one of a wealthy woman, and 2 were found buried with coin hoards, indicating they were an item valued by their owner.

The mystery was also deepened when a metal icosahedron was uncovered in Germany. It bears an incredible similarity to the dodecahedrons, even down to the decorative knobs on the vertices. However, it doesn’t have the large circular holes in the faces, suggesting that the devices use relied less on them than previously believed.



What would be valued by both a member of the military and a wealthy civilian? Possibly some kind of game. The initial theory of the dodecahedron being used for entertainment likely originated with Dungeons and Dragons players. However, it’s not completely without merit. Yes, it’s unlikely they were used as dice because the irregular sizes of the holes would mean they’d always land small hole down. But, it’s feasible that they could’ve been used for other types of games.

One suggestion is a puzzle ball. A string threaded with different sized balls would need to be passed through the dodecahedron. The player would have to thread them through each hole in the correct order to win. Another idea is that it could be thrown and players would have to catch it on a stick.

Unfortunately, neither of these uses explains those pesky knobs, or why anyone would spend so much time and money crafting the game out of metal instead of wood.

Religious Objects

When a biologist can’t explain something’s use, they cite sex, and when an anthropologist struggles, they name religion. Is it possible the dodecahedrons are some kind of religious artefact? Yes. Found alongside the device in a grave in Krefeld, Germany, was a bone staff. This led to the theory that it could’ve been used as the head of a sceptre or as some kind of religious symbol.

Which religion exactly is still up for debate. However, we do know that the Pythagoreans attributed great significance to the dodecahedron. They believed that the classical elements were made up of five different shapes, the Platonic solids. Earth, a cube, Air, an octahedron, Water, an icosahedron, and Fire a tetrahedron. The dodecahedron made up the universe or the heavens and Plato suggested that a god used it for arranging the constellations. He didn’t expand on that.

Knowing this, it makes sense that a scholar of Pythagoras might carry a dodecahedron to symbolise their faith or just to explain the structure of the universe to the less well educated. It’s possible they believed the dodecahedron to be the shape of our solar system, with the holes in the faces representing our neighbouring systems. The different sizes indicating the number of planets in each. The theory would even explain the German icosahedron as a representation of water.

Of course, there’s a major problem with this theory too; you already know it. It’s the knobs. They can’t represent planets, suns or moons as there are 20 of them. However it’s possible they were just there as decoration.


Craftsman’s Dummies

Why were the devices so decorative? Knitting is the only theory so far that offers a practical use for the knobs but we’ve thoroughly debunked that one. A possible explanation is that they, and the entire devices, were simply demo objects used to show off a craftsman’s skill. The complex shape, differently sized circular holes, engravings, and, of course, those decorative knobs would all demonstrate a different skill and amount of precision.

Is the explanation that simple? Maybe, but again, why were they found at military sites, in coin hoards, or buried with the wealthy woman?

Horoscopes and Fortune Telling

The 12 signs of the zodiac offer a final explanation. The theory began as the device has 12 faces, one to correspond with each of the signs. The differently sized holes would help to differentiate between each one. And the theory gained traction when a dodecahedral die was uncovered in Geneva in 1982 with the names of the zodiac signs engraved on each face, proving something similar existed. Perhaps they were used by astrologists or fortune-tellers as divining devices. It was a popular pastime throughout the Roman Empire, and their use in generating an income could justify the cost of manufacture.

How the devices would actually work hasn’t been explained, but maybe they were just props or worn as a decoration on a belt. A slight annoyance is that none have been found with the names of the zodiac signs engraved, which seems like something the Romans would do. But it’s not a big enough issue to completely debunk the theory.

So, is that it? We’ve finally concluded that the 300-year-old mystery is that it’s a device to tell Roman soldiers that they should seize the opportunity to travel and watch out for the colour yellow?


Wait, how many faces does an icosahedron have?




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