The secret medieval tunnels that we still don't understand

Posted by coloneltcb 4 days ago

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Comments

Comment by drcode 4 days ago

Maybe they needed a place to store the dodecahedrons? https://en.wikipedia.org/wiki/Roman_dodecahedron

Comment by vee-kay 3 days ago

The Roman Dodecahedrons were discussed on HN before.

https://news.ycombinator.com/item?id=44565806

https://news.ycombinator.com/item?id=39102069

https://news.ycombinator.com/item?id=24332244

Several theories on their purpose, most plausible (IMHO) is that that they were used for knitting.

https://www.reddit.com/r/ancientrome/comments/17a17ju/roman_...

Comment by pseudohadamard 3 days ago

And they're all wrong. The real use was with a (now decayed-away) wooden ball inside them which, when shaken, displayed texts like "certum est" and "iterum postulo".

Comment by tim-tday 3 days ago

That’s it!!!

Comment by socalgal2 4 days ago

precursor to Shape-O-Toy?

Comment by w0de0 3 days ago

How can this entire thing be written - including the observation that most entrances are “in or near” Christian churches - without even mentioning the extraordinarily obvious conclusion of forced or voluntary anchorites?

There is a deep tradition of chthonic ascetic monasticism in Christianity. Many, many Churches from this same period have attached anchorite cells.

It is easy to imagine similar cells/tunnels being used, unremarked, by choice or coercion.

Comment by readthenotes1 3 days ago

"passages become seemingly impossibly narrow, as small as 16 inches (40 centimetres) in diameter. "

Vs

"and the minimum width between armrests is 39.37 cm (15.5 inches)." https://help.ryanair.com/hc/en-us/articles/31352078107921-Se...

Comment by IAmBroom 4 days ago

FTFA:

This clandestine treatment would have made sense had the erdstall been built as escape routes in case of invaders, but this can’t have been their purpose. They only ever have one entrance, usually located beneath the floor of a church or farmhouse, or simply under the flagstones of a town square.

That SCREAMS "hidey hole in case of invaders", to me. Like the hole Saddam Hussein was discovered hiding in.

If the countryside is overrun with invaders, there's literally no place for peasants to escape to. But if you can safely hide until dark, you have a chance. If you can wait out until the invaders pass through to their objective (strategic castle, opposing force...), you survive.

Comment by crazygringo 4 days ago

Based on just this article, it seems far most likely to me that it was a place to hide during an attack.

> And while three brave explorers in the 21st century once spent 48 hours in an erdstall, crawling to new sections whenever oxygen became scarce, it seems unlikely that they would have been constructed as hiding places, even temporary ones. Though they could have provided refuge for a small family, why would they be accessed from such public spaces?

I don't see why a whole bunch of people couldn't have hidden in them for several hours during an attack/raid? A hiding spot sufficiently known to a few, just big enough. And then it makes perfect sense the entrance would be in some central public place.

> The lack of exits is a further strike against this theory—if enemies became aware of such a tunnel being used as shelter, it would quickly become a death trap for its inhabitants.

Which would contribute to their extreme secrecy. And the loops and dead ends and narrow spots make it all the harder for attackers to pursue you even if they find it.

> Besides, in either of these cases, one would expect at least some goods to have been left behind—remnants of food or clothing, cached or dropped valuables. Instead, there is nothing.

If they were intended for hiding for just a few hours, since oxygen would run out anyways, it makes sense for nothing to be left in there. You rush in and come back out when the raiders have moved on. Clothing was valuable, you weren't going to leave your shawl behind.

Comment by alwa 4 days ago

Indeed: that would help reconcile the presumed secrecy with the fact that, also per the article, there are upwards of 2000 of these tunnel-structures that fall into this category. All across Central Europe. Aggressor knows THAT there's likely a safe-tunnel, but doesn't know exactly WHERE the safe-tunnel is, and whether it's worth taking the time to find...

For that matter—A place to stash the kids from the census-taker and the harvest from the tax man? Tuck them away, just for that day, once every so often, and pull them out afterward?

Or knowledge privileged to some specific order, whose representatives are geographically widespread but sparse within a given community?

Comment by pseudohadamard 3 days ago

Read the paragraph about halfway down:

The erdstall surely could not have been built with storage in mind, since their length and narrowness offer no advantages over a conventional and convenient cellar. And while three brave explorers in the 21st century once spent 48 hours in an erdstall, crawling to new sections whenever oxygen became scarce, it seems unlikely that they would have been constructed as hiding places, even temporary ones. Though they could have provided refuge for a small family, why would they be accessed from such public spaces? Or be too small for a large man or pregnant woman to fit through? The lack of exits is a further strike against this theory—if enemies became aware of such a tunnel being used as shelter, it would quickly become a death trap for its inhabitants. Besides, in either of these cases, one would expect at least some goods to have been left behind—remnants of food or clothing, cached or dropped valuables. Instead, there is nothing

You also need to look at the locations and context. There are several of these things in the region my family comes from and at the estimated time they were built there were no invaders or other problems that would justify using them as shelters. Not to mention that if there were, you'd hide your family in existing shelters in the surrounding forests or hills, not some cramped underground deathtrap.

Comment by crazygringo 3 days ago

Read my comment. I literally quoted half of what you're telling me to read. That's what I'm critiquing.

And you might not have time to bring your family out to the surrounding forests. If these were centrally located in town, they might have been intended just for the people who happened to be in town at the moment.

I'm not saying that I know what they were for. Just that the reasons the article gives for saying they weren't for hiding don't hold up at all.

Comment by pseudohadamard 1 day ago

The ones I'm aware of aren't in the middle of town, and by definition they can't be because they're holes in the soil landscape which is in short supply in the centre of a town. They're near small villages for which getting your family into hiding can be as simple as walking across the road into forests, ravines, etc. It'd actually be much easier to just herd your family into some nearby patch of wilderness than to shove them all into a hole in the ground without food, water, or toilet facilities.

In any case hostile forces don't just teleport into your village, they're moving on foot and stopping to loot on the way, you've usually got weeks of warning that something bad is happening and days of warning that it's about to happen to you. The whole shelter theory just doesn't hold water.

Comment by araes 3 days ago

Tax collector avoidance is actually a pretty excellent alternative proposal. From searching, it looks like a lot of the taxes were on stuff that was difficult to hide, like farm animals owned, and houses / farmland.

However, this site [1] shows several categories for taxation that might be hidden to falsify the taxation basis. Cash, Inventories, Household Goods, Luxury Clothing. Admittedly, it seems like there would be a greater percentage of items left behind in some of these locations, since there often tend to be something. Yet, for taxation avoidance purposes, maybe they're very motivated to recollect everything that was hidden.

[1] https://ehs.org.uk/taxation-and-wealth-inequality-in-the-ger...

Comment by crazygringo 3 days ago

Interesting, but probably you'd hide things like cash or clothing in a small box nearby, buried maybe. Not in a large communal tunnel.

Comment by tim-tday 3 days ago

No way I’d hide in a hole without another exit. And if I went to the trouble to dig a hidey- hole I’d prepare it with a jug of water and a snack.

Comment by crazygringo 3 days ago

If the alternative was being hacked to death, I venture to guess you probably would.

Comment by nosianu 3 days ago

No, the alternative would be that they would have build something tat would much better fit that purpose. You are trying to fit a square peg through a round hole here. The article mentions why all the common ideas don't make sense.

The theories proposed here are merely examples of human brains ability to come up with a fantastic story for anything in the absence of data. Ex falso quodlibet - from zero follows everything, if you have nothing you can just say anything you want, and it will "explain" your non-existing data perfectly /s

The extremely narrow passages, only one exit, bad air circulation, there is nothing that hints towards this being used for hiding, quite the opposite.

> And while three brave explorers in the 21st century once spent 48 hours in an erdstall, crawling to new sections whenever oxygen became scarce, it seems unlikely that they would have been constructed as hiding places, even temporary ones

Comment by crazygringo 3 days ago

Why are you quoting to me something I myself already quoted in order to disagree with...?

I know the article mentions why hiding doesn't make sense. My whole comment is about how the reasons it gives don't hold up.

Comment by sleepyguy 3 days ago

Most likely for woman and children to hide as a last resort, the men would be tasked with defense. Hence the size of the tunnels and the narrow connections. The fact there was nothing found in them could mean they were never needed and not used

Comment by IAmBroom 4 days ago

There's zero reason to expect remnants of food, as well. It was not shelf(tunnel)-stable.

Comment by bluGill 4 days ago

There would still be signs. The food rots - but it would leave traces.

Comment by IAmBroom 3 days ago

Only if the tube was used for long enough to need food.

If you are hiding your family from almost certain death, 24 hours with no food or water in a cool dark cave is a possibility.

Comment by ycombinatrix 3 days ago

The proximity to churches + lack of ventilation makes this theory unlikely in my head. I also feel that some families would have grabbed some food or water before heading down there.

Comment by IAmBroom 3 days ago

Why does proximity to churches matter?

Comment by ycombinatrix 3 days ago

Having your family leave the home & run to the church during an attack seems ill-advised.

Comment by crazygringo 3 days ago

Presumably it's not meant for the entire town. Just the people who are already in town nearby who have enough advance warning. It makes sense to be in a church since that's in the center of town and you can lock the doors to give enough time for people to get into it and cover the entrance.

If your family were at home in the nearby countryside they'd flee into the forest or something instead.

Comment by jurschreuder 4 days ago

Maybe it was like a safe. If people wanted to steel something it would take them a very long time and they would be very easy to stop from ever coming out alive.

Comment by IAmBroom 4 days ago

That's what buried silver hoards are for, which have the additional advantage of being pretty much unfindable after the sod reintegrates overhead.

Comment by kayo_20211030 4 days ago

Is it possible they're the medieval equivalents of dry-wells? Why build something big-enough for people if all you want to do is accommodate run-off or sewage? What's the geology like; porous vs. no-porous? Porous enough for storm drainage, maybe? It seems a stretch to call them secret. Why document something as common as a drain?

Comment by sharpshadow 4 days ago

Heinrich Kusch did some excellent work on this. Here[0] are some video documentaries. Some of his findings will blow your mind.

0. https://www.unterwelt-kusch.com/dokumentation/film-und-audio...

Comment by fatbird 4 days ago

As people spent time in them, the oxygen would run out and be replaced with carbon dioxide, which is heavier than air and would sink to the bottom. With no exits and no airflow, wouldn't this become a straightforward deathtrap at some point? Or were there ways to force clean air to the bottom, somehow forcing out the CO2?

Comment by pluc 4 days ago

Seems to me that a secure hiding place that only works for up to N hours then becomes a death trap is a really bad concept

Comment by crazygringo 3 days ago

If you only need it for less than N hours, though, it might be a really good concept

Comment by _dain_ 4 days ago

Weren't people much smaller in those days? Maybe adult men could have fit just fine.

Comment by d_silin 4 days ago

Not that small (1.0-1.4m).

Comment by IAmBroom 3 days ago

Children were small enough.

Digging a subterranean tunnel with a wooden-bladed shovel is going to SUCK. I'd skimp, too.

Comment by roody15 3 days ago

Think these were made by animals / a long long time ago. They are burrows.

https://youtu.be/7HLqleFVoDg?si=9UdJLMS-pD6G9G5G

Comment by fock 4 days ago

TIL hn will tell me about archeology just a bikeride from my office.

very fun!

Comment by dvh 3 days ago

3 days ago something similar was found in my country: https://my.sme.sk/nitra/c/na-poli-sa-prepadla-poda-vyskum-od...

Comment by d_silin 4 days ago

Medieval children dug those for fun and games. Explains the size and lack of recorded attribution.

Comment by moi2388 3 days ago

“ The erdstall surely could not have been built with storage in mind”

“it seems unlikely that they would have been constructed as hiding places, even temporary ones.”

What about hiding places for storage? As in, smuggling, illegal trade or evading taxes?

Comment by cloudhead 4 days ago

Hyperion, anyone?

Comment by areoform 3 days ago

A lot of folks are latching on to the "hiding place" theory, and that could very well might have been one of the use cases. But as the article points out, the lack of a second exit makes that unlikely.

I would like to offer a competing theory. These are thermally stable storage places for perishables.

As heat transfer is directly proportional to surface area, the ideal vessel that maximizes the volume / surface area ratio would be a sphere (like some cryogenic tanks for rockets). But if you don't have the technology to make that or a cylinder, then the best you can do is observe that lowering surface area helps and make smaller, long rounded passages to try and optimize a ratio that you don't understand by feel.

I think it's more likely that these are are ancient fridges / hot boxes than a way to spiritually experience rebirth. I think a thousand places to store hay for horses and cheese for your family is far more likely.

Could these be boltholes? Yes, but how frequently were places getting invaded? War was mostly siege based and was fairly infrequent for a given city / place (i.e. even if the polity next door was under siege at the time. You weren't) Winter and summer - on the other hand - were and are yearly guarantees.

Comment by wrenky 3 days ago

The problem there is why they have such tight bottlenecks periodically- Why not just have a traditional cellar?

Comment by areoform 3 days ago

Great question!

Perhaps. Perhaps that was one of the use cases, but the inconsistent diameter could also be the result of them being bad at digging tunnels. Digging tunnels by hand is hard (and - dare I say - scary).

Comment by tzs 3 days ago

I don't think being bad at digging tunnels can explain the bottlenecks. They are way smaller than what you'd expect from inconsistent diameter due to poor digging.

Some inconsistency from poor digging can be ignored as a minor inconvenience. It is no big deal if in one section you have to duck a little. The bottlenecks on the other hand are so small that the noticeably impede progress, and some people probably could not get through them at all.

If they are not there intentionally that would be too big of an inconsistency to ignore.

Comment by koct9i 3 days ago

They could be medieval ground source heat pump. Tunnel provides thermal exchange with ground mass.

Comment by secretsatan 4 days ago

Reminds me of the film “The Borderlands”, won’t spoil anything but it’s a good bit of eldritch horror.

Comment by 8bitsrule 3 days ago

Not like the stealing of treasures was a problem ... back in those days.

Comment by pessimizer 4 days ago

Tunnels through which dogs could carry packages or messages no matter what the weather was like and without fear of getting lost or interfered with on the way?

The chambers at the ends could have been where the dogs slept and were fed.

Comment by mmooss 4 days ago

They have only one access point, per the OP, so they don't provide transit anywhere.

Comment by nkrisc 3 days ago

And then returned the message back to the single entrance?

Comment by 4 days ago

Comment by sdbbp 3 days ago

Was there a populist (home) mining fad? People got excited about digging for possible resources and dug crude exploratory tunnels?

Comment by Panzerschrek 3 days ago

Could it be some sort of jail? It can explain, why these tunnels had only one entrance.