[yetanotherloser]

I like that theory too and offer a followon explanation: to make a dodecahedron you must make an accurate regular pentagon and this is not trivial with ancient geometric methods, you need to have learned a thing or two to get there. This makes it a better test than, say, an icosahedron. But we do know that the Roman empire wasn't completely unfamiliar with icosahedral dice, probably for a magical or divinatory purpose rather than determining whether your wizard made her saving throw.

An analogy to this "masterpiece" theory might be the industrial-age "Turner's cube" that demonstrates a pretty solid level of ability with a lathe.

[pclmulqdq]

I think the current view of many scholars is that the Roman D20s were for gaming use as well, if not primarily for gaming use. I would love to see the most recent scholarship on this, though. I assume the actual game is somewhat lost to time: game rules don't generally get written down in any medium that is durable enough to survive thousands of years.

[yetanotherloser]

That's interesting, I thought the case made for oracular use when I read about it was reasonable, but I may be a bit put of date. There was a fair bit of weird belief washing around in later Roman times before Christianity won out, though.

As for game rules - we have a tiny enough fraction of all non-elite-literary writing from antiquity that we probably wouldn't have a complete game's rules if they had been in the habit of writing them down - but we have so many surviving bits of writing that we ought to have fragments of rules. They seem rather thin on the ground, which leads me to suspect that written rules just didn't seem that important to most Romans. From Vindolanda to Oxyrhynchus they wrote bills and doggerel and love-life complaints and demands for new socks... but nothing at all that attempts to explain THAC0.

We don't even really know how they played Ludus Latrunculorum, despite finding quite a few sets and more boards - but there are several reconstructions from literary references. One of them I find quite engaging, so I hope it's on the right track.

[littlekey]

>probably for a magical or divinatory purpose rather than determining whether your wizard made her saving throw.

From a certain point of view these are the same thing

[yetanotherloser]

I had that possibility in mind, yes :-)

[whoopdedo]

> probably for a magical or divinatory purpose rather than determining whether your wizard made her saving throw.

Why should I assume humans playing recreational games is a recent invention?

[yetanotherloser]

Board games are much older than the Romans, though possibly not older than writing - and texts give us a bit of a clue that some early ones were part recreation part ceremonial. By Roman times pure recreational games were common and reasonably often referenced in their literature. They definitely used cubic dice with numbers on for games (and gambling). The icosahedral dice usually have Greek letters rather than numbers (occasionally symbols IIRC) which make them hard to move a piece to or compare scores; we don't seem to find them with game boards like we do "Latrunculi" counters; there's no textual support for a game with them (weak evidence, true) but there's a fair bit for strong interest in divination and oracles that could use them. So not a dead cert, but fairly likely for the D20s. Whereas when you find a Roman D6, you can be pretty sure it's for gaming and/or betting (or a thief's hit points).

[kagakuninja]

Come now... Saving rolls use icosahedrons. Old-school paladins used D12 for hit points, I don't know about 5E.

[yetanotherloser]

If your DM had you use these icosahedrons for saves...

https://mymodernmet.com/roman-20-sided-icosahedron-dice/

then you really ARE old-school.

[KETHERCORTEX]

> you must make an accurate regular pentagon and this is not trivial with ancient geometric methods

Does it need anything else besides some kind of protractor and ruler?

[yetanotherloser]

Making a triangle or square or even hexagon with rule and compass is fairly easy. Making a really regular pentagon also only needs rule and compass, but noticeably more knowledge with them. Try it.

https://sciencevsmagic.net/geo/