[voidUpdate]

> Did the builders knew the earth was round?

Yes. This has been known since ancient greek times, and Aristotle calculated the size reasonably well. Maybe not every labourer knew or cared but the architects almost certainly did

[smeej]

Exactly. I think I'm more annoyed at this point with the myth of the ignorant Medievals than I am with the myth of the flat earth itself.

Even knowing the earth is round, if I were going to put things in a "straight line" geographically, I'd do it with the reference most people would actually use and see: a 2D map.

[Archelaos]

> most people would actually use and see: a 2D map

The expert used spherical mathematics. This was quite widespread knowledge required to build proper sun dials and in the Late Medieval period for long distance navigation. Some were able to use analog computers, called "armillary spheres", for the calculations, which were known since Antiquity.[1]

[1] See https://en.wikipedia.org/wiki/Armillary_sphere

[smeej]

Most people aren't experts. If I'm setting up a bunch of churches in a line to make a point, I'm doing it to make a point to the vast swath of common people in them, not the handful of experts.

[buildsjets]

You have made the assumption that the line-up was done for the sake of human people, whether common or expert. When choosing the site to build a religious facility, would not the sake of the deity(s) being worshiped be a primary consideration?

[smeej]

Honestly? No, not usually, or at least not when the deity has made it clear that He can be worshiped anywhere.

Locations are chosen for the sake of the people who are expected to come to them.

[Archelaos]

Only the experts of that time could have found out that this churches are all lined up according to the Meracator projection, if they had any idea of that projection at all. It seems rather as if your top-secret St. Michael's conspiracy, which, without leaving any written traces, when carrying out its secrete plan over several centuries using advanced cartographic and geodetic knowledge to determine longitudes, was aimed at the mystery-susceptible people of our times.

[crabmusket]

That's not necessarily true. I recently read Barnabas Calder's Architecture: From Prehistory to Climate Emergency which contains several mentions of the incredible detail architects put into their work- from ancient Greece through mediaeval cathedrals. Details and design which would not have been noticed by any eye but an expert's.

I'll try to look up an exact quote later. But the gist of several passages was that there was an elite or expert community- obviously, or nobody would have been designing buildings like this!

Let's assume for the sake of this discussion that the 7 sites are deliberately aligned by somebody. They would presumably be a powerful elite, and would be doing it to impress other powerful elites.

[Archelaos]

You may perhaps be interested in these two documentaries about the geometric principles that were fundamental to medieval town planning:

"Die Entdeckung der mittelalterlichen Stadtplanung" (2004): https://www.youtube.com/watch?v=-ZzEzhIGnwM

"Mittelalterliche Baukunst – Schönheit ist planbar" (2009) https://www.youtube.com/watch?v=MQcKOkbagDc

Both documentaries are in German, but are well worth watching, even if the automatic English subtitles are sometimes a little inaccurate.

[crabmusket]

Interesting! I've added them to my queue, thanks :)

[searedsteak]

I'd say the bigger question is whether or not the projection used at the time of design was one that would show the straight line. The Mercator projection was first invented in 1569 [1]

[1]: https://en.wikipedia.org/wiki/Mercator_projection

[regularfry]

This has to be the core of it. If the underlying question is "was this alignment intentional" then you could start by asking whether there are extant maps with better cathedral alignment than Mercator.

These places are old. Skellig Michael goes back past 823AD, Mont-Saint-Michel is about the same sort of age, and the Sanctuary of Monte Sant'Angelo goes back to 490AD(ish). San Michele Arcangelo is on top of a pre-Christian pagan temple. Stella Maris is on an Old Testament Biblical site. None of them is less than a thousand years old.

The bar for finding a map that happens to align, and then explaining how it was made, is not a low one.

There is a projection that might fit, though: Plate Carrée is definitely old enough, and a brief visual sanity check doesn't make it look totally off.

[smeej]

Why do we need to assume widespread maps for this? Or even maps of the entire globe? A regional map showing barely more than a rectangle with this as its diagonal would be sufficient to get the point across to the average layperson.

Virtually everything in church design is meant to communicate truths of the faith to illiterate laypeople. That's part of why pictures feature so prominently. They're telling stories to people who can't read. The sense of space, and the drawing of the attention upward, they're also communicating to people on purpose.

If the argument is that the sites were not intentionally built in a line, that it just happened this way, that there just happen to be seven prominent hills with churches built on them that refer to St. Michael (or 6 and Mt. Carmel, which is associated with him in another way), I guess that's a different conversation, but I thought the idea here was that these were lined up somehow on purpose, at least for the latter built ones, and were intentionally built to be "in a line" by some meaning of the term.

[regularfry]

The line is long enough for the curvature of the earth, and the subsequent distortion in the map projection, to be relevant. Notice that they're closer to a straight line on Mercator than to the geodesic: that means if you were to use purely local referencing to align the sites, they wouldn't end up where they are. You only get them to line up when you distort the natural geography with a projection of some sort, so if you want to make an argument that they were intentionally built on a line, you also have to account for the systematic deviation from the geodesic. And that prompts the question of whether that's remotely feasible given what we know of the history of cartography.

What I'd want to know is how old the story of St Michael's Sword actually is. Not the churches, but what's the earliest reference to them being in a line. My bet is that it's well after Mercator, and probably safely after the 18th century, when chunks of Europe got geodetic surveys done.

[jameshart]

Knowing the earth is round doesn’t mean you automatically consider a geodesic the most logical kind of ‘straight line’.

Mercator exists because it’s easy to navigate with. It’s easy to navigate with because it preserves bearings. Lines of constant bearing are, when you’re navigating on the ground, much more meaningfully ‘straight’ than geodesics.

‘Keep heading North West’ sounds like a pretty straight line.

[gruturo]

> Aristotle calculated the size reasonably well

Eratosthenes.

https://en.wikipedia.org/wiki/Earth%27s_circumference#Eratos... https://en.wikipedia.org/wiki/Eratosthenes#Measurement_of_Ea...

[voidUpdate]

Sure, Eratosthenes got it more accurately than Aristotle did, but Aristotle was only 5000 miles out, came before Eratosthenes (died about 50 years before Eratosthenes was born) and on the scale of a planet, with the technology he had available, I'd say thats reasonably good

[dhosek]

One of the incorrect things about Columbus that I was taught in second grade was that he had trouble getting support for his voyage because his would-not-be patrons thought the earth was flat. In fact, they refused to fund him because he thought the earth was much smaller than it was and they had the correct size of the earth.

[buescher]

It’s historically rooted in Protestant anti-Catholicism, and the most popular version in America of it comes from Washington Irving.

[cryptonector]

I was taught the same thing by Catholics in Buenos Aires.

[buescher]

Well, now you know where they got it from.

[cryptonector]

Maaaybe. I've not seen any strong evidence for that. It's also possible that multiple groups independently came to think that smearing Columbus' detractors was a useful thing for them to do.

[deepsun]

I wonder how many would-be Columbuses were before him and failed.

[Almondsetat]

It seems strange to include such a question at the end of the article that can be answered with a 5 second non-AI search