The mysterious dodecahedrons of the Roman Empire
atlasobscura.com
atlasobscura.com
> It has also been suggested that they might have been an object to test the skill of a metalsmith, perhaps as part of a portfolio to demonstrate their capabilities to customers or as a way to qualify for a certain status in a collegium (guild). This speculation is based on the historic cost of bronze and the level of skill necessary to cast such an object.
It’s complexity screams “apprentice’s graduating casting project” which would also explain why some were found with coin hoards - they’re sentimental objects kept by successful blacksmiths; the one thing they’d keep to represent an entire career.
The holes would likely have been cut using premade templates so the builders just used a different side pattern on each side, perhaps to demonstrate centering.
[1] https://en.wikipedia.org/wiki/Sprue_(manufacturing)#Injectio...
As an impromptu digital armchair archeologist I'd say this very specific geographic dispersion suggests cultural / religious significance. In any case it weighs against a purely utilitarian role (that would easily diffuse across the empire).
Wax residue was found inside "one or two". Possibly used in a ceremony using candles. The protrusions might have been yarn anchors, not to knit gloves, but to form elaborate ritualistic symbols. I.e. imagine the bare metal covered with a colorful pattern that would be wound and unwound to match the occasion.
Unfortunately a lot of these details about every-day life are lost to history as no one bothered to write it down "as everyone already knows about it".
> Possibly used in a ceremony using candles
It’s possible they could have also used it to hold candles outside of religious ceremonies.
Fishing, toys, music, games, things that were global in the roman empire.
What the map shows is that it was used in the colder parts of the empire.
These wouldn't have been products sold to customers and traded, they would have been symbols that the individuals had achieved mastery within a specific lineage of artisans restricted to that region. Almost all knowledge was communicated via oral means because scribes were very expensive and most people were illiterate - there's zero reason to expect a wide distribution throughout the empire.
And also such objects would be much more rare. Imagine all the objects that have been found and melted down during the last 2000 years. For us to have found over 100 of these so far is already an indication that it was a lot more common than an apprentice piece.
What levels of mastery? Roman historians didn't write much about the ins and outs of their metalworking industry so we don't know how intricate the process was but apprentices graduating is rather universal (their teachers get tired of them or die eventually, after all). Besides, just because it's an "apprentice piece" doesn't mean that it's made by an amateur, but by a skilled artisan to prove they're ready to go out on their own.
> And also such objects would be much more rare. Imagine all the objects that have been found and melted down during the last 2000 years. For us to have found over 100 of these so far is already an indication that it was a lot more common than an apprentice piece.
Finding only a hundred of these makes them extremely rare. Check out Wikipedia's non-exhaustive list of museum collections of ancient Roman and Greek artifacts [1]. The collections number in the tens of thousands of objects each and that's just the stuff a few collections felt was worth keeping - there is tons more Roman artifacts on the antiquities market and huge troves are still discovered on a regular basis [2][3].
From [3]:
> This guy even got his grubby hands on a Roman dodecahedron, an extremely rare artifact (only 100 are known to exist) whose purpose remains an archaeological mystery to this day. A total of 13,246 artifacts were seized in the raid on his home and from several safety deposit boxes he rented in Lorraine.
[1] https://en.wikipedia.org/wiki/List_of_museums_of_Greek_and_R...
[2] https://www.ksl.com/article/24751877/10k-roman-artifacts-fou...
We have many more examples of Roman weapons made up of much more valuable metals that survived.
If bronze is expensive, then poor quality versions could simply be melted down to raw material.
I like this idea. And I struggle to imagine the scenario, because it seems like it would also have social aspects which we can’t know without written testimony.
If the metal is expensive, how is to valued compared to other goods? In the modern world we have tons of stuff, but to what degree is this the same in the ancient Roman world? Who pays it’s cost? If you’re an apprentice could you afford to keep it—especially if you’re not very good (haha).
I'm fairly certain that every-day practices for all of these things were far from universal across the empire; it's a huge assumption to think that, especially considering that we don't actually know all that much about some of these thing and that we don't know what we don't know (e.g. it was only a few months ago that they found evidence of gladiator fights in Britain; it's entirely possible – even likely – that there were wide-spread well-known games in some regions that we just don't know about).
I'm not saying it can't be related to heat, but I wouldn't be so quick to jump to that conclusion based solely on the location where these things were found.
Each object has 12 sides, so 12 holes. For hundreds of exemplars thats thousands of holes. The holes are described as having different sizes on the same dodecahedron. For being an object of mystery, one would assume a catalog of features to have been constructed, but I am not aware of any.
I believe they were used to test coin sizes (could be used by both scrapers and verifiers), see my comment at https://news.ycombinator.com/item?id=35946841
Such a hypothesis should be testable: catalog the hundreds of dodecahedra, one row per item, and 12 columns for the radii.
Collect all occurring thousands of radii and sort, and observe density peaks and compare age of item and coins of era with radii.
No one is certain what Roman bronze dodecahedrons were used for (2018) - https://news.ycombinator.com/item?id=29717215 - Dec 2021 (207 comments)
What were these Roman objects used for? - https://news.ycombinator.com/item?id=25237271 - Nov 2020 (37 comments)
The Mysterious Bronze Objects That Have Baffled Archaeologists for Centuries - https://news.ycombinator.com/item?id=21439351 - Nov 2019 (7 comments)
Should those be “Easter” and “meeting”? I’m not sure if these are misspellings or spellings I’m not familiar with.
That in 325 AD the vernal equinox fell on 21 March in the Julian Calendar was just a matter of fact. No one except of a few experts cared for more than a thousand years, that the calendar date of the vernal equinox gradually changed, amounting to 1 day aprox. every 128 years.
The "classical" way to "measure" the date of the equinox is by using a so-called gnomon, a vertical stick. At the date of the spring or autumn equinox, the tip of its shadow over the day results in a straight line. Here is an illustration and a longer explanation: https://earthsky.org/human-world/equinox-shadows-trace-a-str...
It's not like anyone actually writes down house decoration theory. You just sorta pick up on it based on visiting a bunch of people's homes in a community.
And going back to the original question, making those dodecahedrons would have required considerable expense, skills, and effort. That's not the kind of thing that can spread as a low-effort fad, and an artist who's going to spend that much time on something would be even less likely to make an exact replica rather than something original.
Another theory of mine is a candle holder which adapts to stump size.
This one sounds most plausible to me, given some were discovered with coin hoards.
In the past coins used to have simple round edges. People would scrape (with say a knife or other hard tool) metal from coins slightly reducing their diameter imperceptibly.
This tool could be used both by scrapers and verifiers. After a daytime trading job a scraper might sort his coins by type, and do the pass vs no-pass test. Scraping ones that were slightly larger than average, but not those already scraped by others.
A verifier that doesn't scrape, but wants to avoid incurring loss due to scrapers might use the tool during trading and refuse coins that fall through, or he might more discreetly sort the revenue after work, and sort into coins to keep, and coins to return as change.
I don't know if Isaac Newton was the first to introduce the slotted edges to deter scraping, but he did locally introduce it when he was appointed head of the Royal Mint.
They were made with a copper alloy and thus conduct heat efficiently. That also aligns with the reasoning used to justify the gloves theory (i.e. they were primarily found in colder climates).
Also not convinced it will be all that stable as a candle holder.
I actually like any theory related to heat because that's what the map indicates. Any other theory is related to things and actions that were common throughout the empire.
As for heat: how did people heat their homes? Rich people had their fancy underfloor heating, but what did poor and middle-class people use? In Celtic and medieval times they would typically use a hearth (i.e. fire) – it seems to me a candle just doesn't give enough heat, and you're going to need a hearth anyway for cooking. I would imagine that's also what they used during Roman times since that's what's used both before and after the Roman era.
I'd love to have a replica for that purpose, I wonder if someone makes them.
Edit: of course they do, one search away. A nice conversation starter :)
On the outside the protrusions could have been used for tying ropes that secure the joint to the pole. Could have been very strong if also threaded inside the dodecahedrons as well. All reusable and modular. Alright, may be a total fantasy though.
The thing that nullifies this as an idea for me is it would be expected therefore to find absolutely thousands of them. I don't know enough about it, but I got the impression it's much less than that, and it'd seem brass would last better.
--nvrmnd. Apparently there's only 1. Cube
Though, makes me wonder - what about when constructing domes?
As there is only ambiguity in the analysis of these, according to the article, then my conclusion is that no dodecahedrons have been recovered showing evidence of being used like this.
that is a holy hand grenade
I've crafted a few in various media. Getting it right is tricky. Really makes you appreciate 3d printing.
Or maybe they’re more like fizzbuzz for gallo-Roman bronze artificers. You show up at an interview and they ask you to knock out one of these to prove you’re not an idiot.
If this were the case, shouldn't there be makers' marks on them? Something to identify them as being the work of a journeyman level artisan hoping to use it to prove their worth? Otherwise, one could fraudulently present someone else's work as there own, and undermine the system.
I feel that if they were really part of a 'graduation portfolio' for crafters, it would be much more obvious. Something like an inscription that says "crafted by Albertus in the 14th year of the Emperor Foo".
I like your fizz-buzz theory. If the object is a one-and-done throw away, then you might not bother to put your mark on it.
Seems pretty specific to span two centuries of known construction. Why would they be saved and not recycled? Nearly every medieval village had a blacksmith, with larger population centers supporting more, within the whole of medieval Europe thousands of blacksmiths at any one time, so why have only 116 of these turned up when there should be hundreds of thousands of them?
I think it's very interesting their construction appears to cease just in time for Christianity to take over Europe in the late 4th century. Previously, Rome had 12 principal deities.
So, if we're talking about casting, then we have to ask what did they cast in, and what did they use for the molded object? I don't know when sand casting was invented, but I think that's how a lot of modern casting in bronze is done. As for the original piece that was molded, you could do a lost wax type process, and wax was certainly a thing available back then, but would it have been used for this purpose? And how would you do lost wax with sand casting? If it wasn't a lost wax process, then how did you get all those neat little knobs, because otherwise you'd get the equivalent of mold tear outs.
Any sand casted piece would have needed a lot of cleanup to make it look nice, so you'd need to cut, sand, and polish those edges and surfaces.
It would be interesting to have this discussion with someone who is well acquainted with the process of casting bronze, to see what their thoughts are.
That’s what I recall from last time this went around at least.
The process to make one of these dodecahedrons involves geometrically constructing a pentagon, forming it into a mold, casting from that mold 12 times, centre-finding either the mold or each pentagon, forming a centered circular hole on each given center, joining the 12 pentagons at precise angles, casting 20 spheres, and joining one sphere to each vertex.
The ancient Greek mathematicians were fascinated with compass-and-straightedge constructions (https://en.m.wikipedia.org/wiki/Straightedge_and_compass_con...), and posed (and sometimes solved) many such constructions, particularly constructions of regular polygons (https://en.m.wikipedia.org/wiki/Constructible_polygon). Constructing a right angle from a line is almost the most basic operation, and repeating that two more times constructs a square, so squares are trivial to construct (4 sides, trivial). The process for an equilateral triangle is not quite trivial, but it is simple (https://en.m.wikipedia.org/wiki/Equilateral_triangle) - simple enough that its proof is given at the beginning of the first book of Euclid’s Elements (3 sides, simple). Doubling the sides of a given polygon is also simple, so from a triangle you can get a hexagon (6 sides, trivial), and from a square you can get an octagon (8 sides, trivial).
That’s 3, 4, 6, 8 - what about 5 and 7? For constructing the heptagon of 7 sides, the Greeks considered this problem to be “obstinate”; I believe Gauss was the first to prove it is actually impossible.
For 5, the regular pentagon, constructions using just a straightedge and compass were given by Euclid in Elements and by Ptolemy half a millennia layer, but they are certainly not simple (here is an animation of one such method https://www.mathsisfun.com/geometry//construct-pentagon.html).
The full list is something like
3: simple
4: trivial
5: hard
6: trivial, just double a triangle
7: obstinate, later shown impossible
8: trivial, just double a square
9: obstinate, later shown possible but extremely hard
10: trivial, just double a pentagon
11: obstinate, later proven impossible
12: trivial, just double a hexagon
So among the first several regular polygons, the pentagon is by far the hardest to construct that wasn’t obstinate/impossible at the time. This makes it the perfect shape to test a geometer’s skill; they would have had to understand the hardest shape in the first book of Euclid’s Elements.
(Centre-finding on a pentagon is also somewhat complicated relative to the other shapes, though not by as much as construction: https://youtu.be/RxYfdNrt4Sw)
Next we move to the dodecahedron. There are only five Platonic solids, believed at the time to have special properties such as being the building blocks of all matter. Three of these are built from triangles. Of the other two, one is the cube built from squares, and the other is the dodecahedron built from pentagons. The cube is fairly trivial and triangles can build multiple Platonic solids, but the dodecahedron feels more unique: it can only be built from pentagons, pentagons only build it, and pentagons are the hardest shape that build a Platonic solid. I suspect this synchronicity would have inspired exactly the kind of awe that a master craftsman/geometer would have liked to command.
Why not stop at the dodecahedron? Making and attaching the spheres to each vertex demands another kind of metalsmithing skill, that of forming spheres, which is largely unrelated to all the constructing of polygons done before. It also makes the object testable by non-geometers: place it on any flat-ish surface (it doesn’t need to be perfectly flat as long as you always have the base spheres in contact with the same five points) and the sun passing through the two differently sized holes will form a specific shape, a lens (sort of the like the shape of an eye, the shape made when two circles intersect a bit). Each lens would be a different size but the same shape, you could visually confirm they were all the same, and more rigorously test the accuracy with just a compass.
Essentially, this object would let you prove to a smart non-geometer (such as a property owner looking to hire an architect to oversee building a house, or a factory owner looking to prove you could manufacture precise and repeatable objects…) that you had excellent geometry skills, and likely that you had read and mastered at least several parts of Euclid’s Elements (the first major “textbook”, widely considered one of the most important and influential books ever, by far the most logically rigorous [important mindset for engineers…] text around and not surpassed in that regard until the 15th century or so, etc…).
If it was made of metal, it also demonstrated important metalworking skills like accurate mold forming, repeatable casting from molds, and joining at precise angles - since errors in metalsmithing at almost any stage would have deformed the resulting verifiable lens shape sunlight makes when passing through it. If it was made of stone, it would demonstrate the same geometry skill and similar skill in stone-working; if it was made of wood, it probably wouldn’t survive to be found as a historical artifact. On top of all of that, it lies at the confluence of solutions to several hard problems in contemporary geometry at the time and it happened to have the same number of sides as there were Gods in the pantheon and it invoked the (religiously-imbued) Sun in verifying its accuracy, all things which would have carried cultural importance and increased the standing and respect of geometers in society.
The calendar theories are certainly interesting as well, but if it was used for such utilitarian and important purposes, there should be correspondingly more utilitarian examples of this object, since there were so many farmers.
The biggest point against my theory is that if it were true, it absolutely demands that these objects would bear a maker’s mark, and they don’t seem to have those. I don’t know how to resolve this fatal objection; I could say it was considered heretical to mark (a representation of) a Platonic solid with a mere human’s name, but this seems a meager excuse.
Roman fidget spinner
(i.e. an object to play around with your hands to keep you more calm)