Massive Medieval structures

Question

A lot of Medieval fantasy works feature enormous constructions. A Song of Ice and Fire, for example, has immense castles like Harrenhal, Winterfell and Riverrun, and of course the Wall. Lord of the Rings has Minas Tirith, the Endless Stair, and much more.

Without invoking magic as an explanation, is it plausible that people, using Medieval European technology, could construct immense castles? If not, what are the main obstacles preventing this?

To be more specific, I'm talking about stone walls higher than thirty meters, towers more than double that, et cetera.

Answer 1

Yes, they could, if size is the only criteria.

Medieval builders could build large structures. Windsor Castle and Notre-Dame are just few examples.

What was lacking (compared to classical period) is the economy and logistics. Building large stone structures was a decade-long effort straining the entire dukedom or kingdom. Basically, you need to free a large number of laborers from sustenance farming and direct them to building. If that is possible, then yes, we can have very big structures.

Answer 2

Without invoking magic as an explanation, is it plausible that people, using Medieval European technology, could construct immense castles? If not, what are the main obstacles preventing this?

Lack of knowledge was the main limiting factor. If we stay in Europe, Romans were capable of building wonders like the Pantheon and the Coliseum, but those techniques were lost after the fall of the empire. Therefore they needed to be learned or discovered again.

It took the Renaissance to reach again that level of skill. However, for just building walls with no other fancy features, it was something possible in the Middle Age, as long as resources were available.

Romanic cathedrals are an example of this, and the small windows were a consequence of the "I don't know how to make a big hole in this wall without having it collapsing" problem.

Answer 3

One major factor holding Medieval Europe back from building huge constructions is logistics. Society just wasn't capable of providing all the labor and materials necessary for building huge structures like Minas Tirith. It took centuries to build cathedrals because limited labor was available at every step of production. There are few quarry workers to gather the stone, few porters to move the stone, few carpenters to build the scaffolding, and few masons to place the stone.

I mean, look at the difference in army sizes between Medieval and Classical Europe. At the Battle of Cannae in the Second Punic War, the Romans deployed between 86,000 and and a 118,000 soldiers. And that was a brand new army, and they were wiped out. Yet Rome was able to replace them and win the war. So it's likely that +300,000 Romans fought in the Second Punic War. Compare this with the Battle of Hastings. At Hastings, the Anglo-Saxons had between 5,000-13,000 men, against the Normans' 7,000-12,000 men. You can clearly see the civilizations of the Classical Era had much more wealth they could throw at problems.

I think this compounds the other answers' engineering concerns. You don't need to know how to build huge buildings when you couldn't afford to anyways.

Answer 4

ASOIAF's The Wall had actual physics problems, which were handwaved with magic. IIRC, the rest of your examples are just engineering, materials and construction problems.

The main thing you're looking for is compression vs tension loads. Stone (or unreinforced concrete) can handle huge compression loads, and it doesn't take a lot of engineering to design big structures or skill to build them, just an enormous amount of manual labor. They can also last indefinitely, which helps justify all that labor.

However, stone does not handle tension loads well at all, and that's what you look for any time you have holes or voids in a structure. Good engineering (e.g. arches) can partially solve that. Wood is better at tension loads, and it's obviously also a lot lighter than stone, but at the cost of permanence and/or maintenance.

A common tactic was to use stone walls supporting wood floors and roofs, which enables quite tall structures. However, there is still an engineering limit because the walls of lower levels must get thicker to support the ones above, and there is no point in going past a certain height because the lowest level's walls get so thick that it approaches completely solid.

Just eyeballing it, many fantasy structures seem to be well above that limit. Worse, many appear to have stone floors and roofs, but we can be charitable and say they're just thin tile over a wood structure. Still, it's hard to imagine many of them getting even half built without collapsing if using medieval materials and methods.

Answer 5

The nave of Notre-Dame de Paris is 35 meters high, and the towers are 69 meters. Cathedrals were built tall for aesthetic reasons and bragging rights.

In castle architecture, height was not that important if it was sufficient to make scaling the walls difficult. A good field of view was often obtained by building on top of a natural hill rather than by built height. Without needing to be as tall as the tallest cathedrals, castles could be large constructions - see Crac des Chevalier

The big question is why would one want to build a 30 meter wall or a 60 meter tower for a castle. Think of the time it would take to get fighters, equipment, and things to drop on attackers to the top of a 60 meter tower. A shift change would involve climbing the equivalent of a 20 floor office building with no elevator.

Answer 6

As I remember, most of the architectural wonders in The Lord of the Rings were thousands of years old. The newer ones were often less awe inspiring than the older ones that they copied, fitting in with Tolkien's theme of the world tending to become more mundane and less wondrous and magical over time.

So if you have architectural wonders in your story, they might be relics of a more advanced ancient society that has fallen. Something like remaining Roman buildings in medieval western Europe.

So you might assume that the Medieval Europe like setting of your stories not only has the medieval society building a few structures as grand as anything built in Medieval Europe, or maybe a bit grander, but also has a number of ruined or intact structure surviving from some fictional version of a Roman Empire, some of them perhaps much grander than any known Roman buildings, and perhaps some of them inspired by the greatest architectural feats of China, Indochina, India, Achaemenid and Sassanid Persia (especially the palaces at Ctesiphon and the "Throne of Chosroes"), ancient Babylon, and ancient Egypt.

And see my answers to some questions:

Could a supertall building have been built in the 18th century?1

Tallest building possible by the Roman Empire2

Practical height of towers without elevators3

Maximum Size Limit for a Wooden-and-Bamboo Neo-Ziggurat4

Architectural feasibility of a tiered circular stone keep5

Answer 7

When talking purely about stone work fortifications like castle walls, they can be made REALLY tall just by stacking because stone can handle compression forces so well, but the big limitation of medieval building height really comes from how much compression the ground can hold up. Modern super tall buildings rely on first digging a foundation down to the bedrock. That way you have a continuous line of materials that can take that kind of compression all the way down.

Medeville buildings in contrast were limited by using "floating" foundations generally made only a few feet down at the most. In many regions this could mean that walls more than 10-20m would just sink and crumble, but in others, where they have exposed bedrock to work with, they could build these super high walls just fine given enough time and resources.

Another work around often used by medieval fortifications was to take advantage of natural elevations. Many castles were built on hills so that the natural elevation would compound with actual wall heights. Normally these hills were chosen not because they were the tallest and steepest, but because they were good enough while being in strategically important places. That said, a medieval castle built into a natural feature like the below image could result in one that looms even taller than many of these fantasy super castles using only medieval technology because no free standing walls would actually need to be more than a few meters high.

Answer 8

A few things come to mind:

1. Materials

There was no Steel used as construction material and (almost) no concrete, so there was only stone, bricks, mortar, and wood.

2. Structural Systems

It's also very important to notice that the configuration of the structural elements in a building is of vital importance, they transfer the loads in the building to the foundations. Many of those buildings heavily relied on arches (for their compressive strength) and on walls with external supports (next edit), but these come with their own limitations. Also, as they were made out of stone, the weight was huge.

3. Technology

One limiting factor on how tall we can build is how high we can raise materials. How to get the stone pieces cut right and then bring them to the construction site is another problem; stone that was not cut evenly might fail easier, thus yielding more material losses (time and capital).