Architectural History for Gamers, 1a: medieval and early modern forts

You may recall in the last installment I said that walls weren’t that big in the Neolithic. That’s the sort of statement that’s liable to get me some blowback, because we have a bunch of sites that have been inhabited since the Neolithic, and nearly all of them went through a long period of having walls – particularly the grand dame of ancient walled enclosures, Jericho.

But they really grew out of – and on top of – the old Neolithic settlements, by simply filling the old buildings with rubble and layering new buildings on top, constructing a tell mound, which is probably the root idea behind so many megadungeons under cities.

detail of excavations at Jericho, looking atypically not-ochre

….so the idea of raising a walled fortification just might be an accident of history: the imitation of a prototype that happened as a bi-product of long habitation. The obvious corollary, for gamers, is that city walls are probably dungeons. Either straight up labyrinthine shells full of working monster ecologies of backfilled ghost cities, filled with undead/spirits/genii loci.

of course, this sort of thing doesn’t happen by accident.
It took religious weirdos centuries to shift all the
bones of Paris’s ancestors into an unmapped maze
under the city center

We get from the tell mound to the deliberately-constructed city wall via some very heavy Sumerian protesting:

“Go up on the wall of Uruk and walk around, examine its foundation, inspect its brickwork thoroughly. Is not (even the core of) the brick structure made of kiln-fired brick, and did not the Seven Sages themselves lay out its plans?”

The author(s) of Gilgamesh were big on big walls – tall and thick, immune to sapping – the kinds of walls you could ride around on a 4-horse chariot to bring the Kingly Presence to all parts of the city’s defense.

Why? What were these walls defending against? Battering rams, sure, and lots of dudes with spears.

secretly I think this is an early form of that stuttering
multi-image thing anime does, to show someone’s going
very fast and hard

And maybe, sometimes, well into the late bronze age, catapults. But I think the big disruptive technologies, which meant Çatalhöyük type mounds were no longer enough, were horses (which encourage retreating to a fort) and bows – missiles with reach. It’s very hard to make a spear reach effectively higher than about 12′ from the ground but a bowshot… that makes high, thick, sheltering walls a necessity.
(swords, BTW, are crap for attacking castles, movie cliches notwithstanding. Unless you can discount the high wall somehow, ie negate the castle bit, a sword is a heavy, useless encumbrance with no reach or strength. Movies love to show heroes with swords attacking castles but they always just project them to the top of the wall where they can melee. Here I’m firmly on team spear or, better yet, pike.)

The castles we know are shaped by horses and bows.

Yeah, so, the Vikings attack coastal France and start calling it Northman-dy and then they attack England with arrows

surprise! there’s controversy about whether Harold really got shot in the eye!

and then they pacify the countryside by building a bunch of these instant-tell-mound+wall forts – motte and bailey castles, where the tell (motte, “mount”) is made from wooden baulks plus dirt, a walled keep is built on top, and a wooden palisade is put around the whole thing, enclosing a training yard and animal-pens. The basic design has been around for a couple of thousand years, but the Normans suddenly start pumping them out pseudo-industrially.

Where the Vikings raided, the Normans go on punitive expeditions to extract “taxes” and then retreat to their castles when the locals start to organize against them. The whole trick with this kind of colonialism is to work the locals as hard as possible and hide all the surplus they produce inside your keep. Then when they come with pitchforks you barricade yourself inside and threaten to set fire to the grain that’s stored against the coming winter.

Then when the peasants’ brief moment of unity passes, you use the castle as a hardpoint for raiding the surrounding countryside. The same basic pattern spreads from Denmark to England to northern Europe to Sicily – everywhere the Normans go.

Reconstructed keep of Saint Sylvain, 1040 CE

Chateau de Gisors, Anjou (Everything looks better in France)

The Vikings/Normans don’t invent the motte-and-bailey, nor are they the last to build them. Dutch wool traders, for instance, had maintained their own Vliegburcht (“flight fort”) in the middle of Leiden, from well before the Viking incursions to the 19th century – it actually got used during the 17th century wars.

the Leiden Vliegburcht/burg, built 449 by some Angle or Saxon

It’s weirdly hidden behind a load of ordinary-looking houses today.
Even though it’s startlingly tall, you can’t see it from the canal at all.

So the thing with these flight forts (and all forts, frankly) is that they’re not big enough to shelter everyone in the community. Typically it’s the administrators, the rich ruling families (same people in the Netherlands), and the dedicated military folks who get to benefit from the walls. Middle class weavers, shopkeepers etc… more likely not. Frankly, the whole concept works best when you have a completely militarized society, where there’s a strong division between fighting folk and the commoners who support them. Like, say, the knightly orders that came out of the Crusades.

Krak des Chevaliers, Syria – one of the headquarters of the Knights Hospitaller,
converted from a Kurdish fort… so, a Crusader castle on both sides.
It’s pretty much the apogee of the horse-and-bow fort.

The basic form is the same as the motte-and-bailey, just… heavily ramified. It’s not self-sufficient; it can only survive through constant resupply or constantly raiding the surrounding countryside (the Hospitallers do both). In many ways it’s like an industrial outpost – a loot factory.

The wall-and-courtyard form is repeated two or three times, so it’s effectively a castle-within-a-castle. The outer wall, crenelated and pierced with arrow slits, is all about giving defenders arrow superiority. If your invaders include Orlando Bloom and inevitably jump up on top of that wall then you fall back to a second motte inside the first, and so on, fighting all the way back to the high tower, which contains not the princess but the chief administrator. If you’re feeling bold and murderous you actually might open the front door and let enemies into the courtyard between the outer wall and inner stronghold, the better to murder them in captivity, from both sides at once.

At root, it’s all about visibility and bowshots.

I show you Krak des Chevaliers because it’s still a pretty businesslike presentation of a castle. If instead you go to Carcassonne, in southern France, you’ll have fun and some great food but you’ll get more insight into 19th century aesthetics than 12th century military practice, because they were heavily romanticized by the visionary architect Viollet-le-Duc, a man whose plans for beautifying France included recarving some of the Alps for picturesque effect. His restoration is fascinating, but not nearly as reliable a guide to any particular historical moment as he would like you to think.

So anyway, back to practical fortification. The logic of horse-and-bow forts is to make attacking more expensive – forts are sometimes rated by the ratio of deaths expected among attackers and defenders. The main way this works is making the bows of attackers less useful than those of defenders – it’s harder to shoot up than down, and bowmen atop the wall can effectively generate a killing zone around the wall. They keep attackers in a vulnerable position looking up (where stuff can be dropped on their heads) for a long time (while they’re trying to climb the wall). In practice, seizing such forts was fairly rare. Instead, you would besiege them: the attackers can’t get in but they can keep the defenders from getting out, which leads to a game of patience chicken, where attacker and defender dare each other to sit still and starve. The forts are warehouses for food, water and fuel, often enough to last multiple years – and sieges would continue accordingly. An army in the field, on the other hand, is a disastrous ongoing expense – not only does it need constant shipments of food, water, fuel, men, and other supplies, it ties up huge numbers of workers, preventing them from doing their regular jobs, like farming. And armies are significantly more expensive to maintain in winter than in summer – first they can march faster and easier in summer, second, it’s easier to get supply caravans to them when the roads are dry and firm. Keeping a besieging force in the field over winter is the sort of thing kings have to plan ahead for, storing up surplus crops for many years.

Aside: In the 14^th century the city-states of Florence and Siena spend so much time besieging each other, they risk bankruptcy and capture by other city-states. In the end the Florentines resort to flinging dead donkeys over the Siena wall, to induce plague. Some mystery disease does, indeed, break out and Florence is finally able to definitively take away all Siena’s toys. Nowadays Florence is a somewhat modern city, while Siena is a museum town… ie a much better place to see some unusual medieval architecture.

So.

From ancient times to about 1350, castles like this (walls of ancient Rome) rule supreme. But then everything changes when the Mongols attack – not quite overnight but… over a century or two.
Aside: D&D’s supposed period, based on its technology, is the late 14th c, which is super weird – it’s like the very last gasp of this long castley era, perpetually stuck on the indrawn breath right before it collapses.

Here Come The Guns (Prologue Montage):
– around 1000, somewhere in northern China, a bald monkish guy comes up with a dust that goes bang.
– By 1200, shipboard cannons have been developed that are good enough to kill the king of Vietnam.
– In the 1300s Mongols, Mughals and Ottomans start building big cannons for knocking down castle walls,
– and in the late 1400s, Europeans, having had a bunch of their castles reduced to rubble, think they might give this new technology a try. The inflection point for this is usually cited as the Fall of Constantinople to the Ottomans.

This particular gun cracks me up – it’s a rebuild
of the cannon used to demolish the walls of Constantinople.
The Ottomans had to bust a Hungarian gunsmith called Urban
out of jail in order to build it, and the gun was named after its creator -.
so this gun that blew holes in the most celebrated walls in the medieval world?
Urban renewal.

The Fall of Constantinople (1453) is a mighty legend, because the walls of Constantinople were themselves legendary. Built before the Roman apocalypse, they were one of the first places that stopped the Arab conquests dead. Then they rebuffed the Kievan Rus and the Bulgars and the Ottomans (4 times!)… while the population of the city withered to something like a 20th of its peak, laid low by disease, unemployment, poor food supplies, and Venetians. By the time Mehmet the Conqueror got around to blasting the walls in 1453, he’d already demonstrated the technique on all the major castles of the Balkans and Levant. So you might think that the crowned heads of Europe would already be looking on uneasily, but… Constantinople was a name. People figured if you could sack it there, you could sack it anywhere.

Is there any better way to commemorate people being dismembered
with explosives, that to embroider images of the event laboriously
into a curtain? The Battle of Pavia, 1525,
where the Italians beat back the hated French

So France immediately starts investing in cannons and hiring cannon-founders and cannoneers. And then in 1499… they attack Milan with them. The walls of Milan were local legends, second only to those of Constantinople in the minds of Milanese worthies, until Louis XII’s cannons knock ’em down, and then Pisa the next month. Several Italian city-states stop squabbling with each other long enough to get their brightest minds working on a new kind of wall – the trace italienne: a rammed-earth rampart, which could disperse the impact of the cannon ball. Michelangelo is one of its first architects of this new fort style, being made “governor and general prosecutor of fortifications” of Florence in 1529. When Leonardo offers his services to the Pope and eventually the King of France, it’s principally as a fortifications engineer versed in the trace italienne and only incidentally as an inventor, natural historian, and artist (he winds up in Amboise, France in 1534, which probably annoys his Italian friends).

The trace italienne plays to the weaknesses of 15th and 16th century cannons, just like the old medieval high-walled fort was designed to generate bow superiority for the defenders. Early cannons are very inaccurate – not really all that useful for indirect fire, where the projectiles fly a long distance and rain down on defenders – that’s more an 18th century thing. People mostly either fire early cannons more-or-less horizontally on a flat trajectory or use wildly inaccurate high-trajectory bombards, parked right under the walls, which rely on medieval defenders being surprised. So the trace italienne puts a load of inconvenient ditches and an angled glacis around the walls, to make it hard to drag heavy cannons anywhere near the defenders and to generate a wide killing zone around the castle, plus slopes to scatter flat-trajectory cannonballs uselessly upward.

The defenders’ own cannons turn the ditches and glacis into a killing zone, but they’re only really effective at the job if there are several lined up in ranks together. And they have blind spots (“dead zones”) near the walls. So you angle them into each other by mounting them on projecting bastions, to generate interlocking fields of fire, so there’s never a safe corridor by which attackers can approach. That’s why the forts are characteristically star-shaped – the star is surrounded by triangular killing zones where you can get shot from 2 or more lines of guns.

turns out this basic idea had been around since the Roman empire, when it was applied to bows

Italian architects were already primed to be excited about star shapes, which had featured heavily in utopian ideas of ideal cities since the 1450s – Francesco Sforza had commissioned a bunch of star-shaped designs for rebuilding Milan… which were never built.

Filarete’s 1450 design for the city of Sforzinda (named unsubtly after his patron)
features a House of Vice and Virtue, a ten-story structure with a brothel on the bottom
and an academy of learning at the top

So the demands of the new fortification quickly get wedded to enlightenment ideals of mathematical perfection to produce a novel kind of Vitruvianism (essentially the idea that The Best architecture will generate The Best society) based on ideal forts, which would naturally be symmetrical, have social hierarchies clearly expressed in them by height and centrality and so on, and best of all, be awesome showcases for the complicated mathematics that their architects had mastered.

Scamozzi’s 1593 design for Palmanova, which actually did get built –
a defensive fort-town in Venice’s agricultural hinterland

Bastions settle down into a broadhead-arrow shape, formalized as the ravelin. And ravelins become a whole field of art in their own right.

The Dutch, of course, incorporate canals and barges in their defenses, the better to move heavy stuff like cannons around.

This design would never have worked in the bad old days of bows, when attackers could surround a single bastion and cut it out of the defenses, but the new, longer range of cannons allows the killing zone to be extended far out into the surrounding countryside, so attacking any one of these detached bastions means facing the cannons from 2 or 3 of them plus the city wall defenses. Suddenly you can plan out whole valleys as killing floors, where attackers are always overlooked by multiple cannon nests. Infantry tactics and armament change, mercenaries develop into the first standing armies, and before you know it everyone’s talking about a military revolution.

Since you can now detach ravelins, you can also leave them open at the back to allow their defenders to rush out for bayonet work (confident they can retreat to a secure fort long before the cavalry get anywhere close), leading to the invention of demi-lunes…

demi-lune of St. Etienne at Besançon, after the city transferred to France
from Austria, which had received it as a wedding present from Spain,
which had received it in marriage from Burgundy.

demi-lune at the Castillo de San Fernando, a masterclass in ravelin architecture

…so you have a new form that’s associated with violent power. It’s big, extravagant, and mathematical. And this is the Baroque period so, of course, like everything else it becomes… a feature of ornamental garden design. (BTW we live in a neo-Baroque era, so if you think the violent garden thing is funny, then… this)

OK fine this one is 19th century neo-Baroque, from Magdeburg,
but mock fortifications were totally a thing in Louis XIV’s palaces.

As usual, though, the future is very unevenly distributed…

Pendennis keep, Cornwall, England, constructed 1540s.
Part of Henry VIII’s massive coastal defense spending spree
after he embroidered a giant target on his back by
declaring himself a heretic – the Spanish would
finally get around to sending the world’s largest
death fleet after his younger daughter in 1588.

By 1545 the English have just about caught up with the Balkans a century earlier – they have cannons but their forts are still high-walled medieval style, with cannon-ports instead of arrow slits (see also Dubrovnik, or “King’s Landing,” to TV audiences). In the middle of their little Tudor civil war, they become aware that their fortifications are obsolete as they’re being built, so during Elizabeth’s reign they get reworked to bring them more up to date…

Pendennis castle, long view, complete with earthwork
cannon fort surround, constructed 1597.

OK, but back to the future: the Netherlands (long regarded as a “defended garden” by the Dutch Stadthouders) develops a more or less completely militarized countryside via a network of ditches, enceintes, and gunboat canals. Remember that burchtfort in Leiden? Here’s what Leiden looks like now (with fortification canals dug during the 1590s):

3 lines of defenses: the burchtfort in the centre (small circle), a partial ring of canal/ditches showing the old (14th c) moat around that, and then a wavy canal of cannon fort bastions enclosing a rough rectangle around that.

Of the many great fortifiers that follow during the 17th century, two names dominate:
van Coehoorn (1641-1704), who did Berlin, Karlsruhe, and many other Dutch and German cities;

Berg op Zoom, the portfolio piece that got van Coehoorn the Berlin gig

and Sébastien de Vauban (1633–1707), fortifier-royal to Louis XIV. Both men are masters of artillery, the key qualification for a fortifier: both develop new methods for attack and defense, acting as their own arms race.

Between them, they invent trench warfare – the only way to attack a fort city. Cannons fire in a flat trajectory, so the way to approach them is by digging tunnels or open trenches, below their sight-lines. When artillery eventually becomes accurate and powerful enough to hit a town over the horizon, defending cities, even with walls like these, becomes effectively obsolete… but trench warfare remains viable through the American Civil War and WW1, provided you can create new trench forts quicker and cheaper than artillery can find and destroy them – that’s why WW1 essentially turns into a giant trench-v-trench sapping exercise.

Since cannons become the key to wars, and sight-lines are key to using cannons, warlords quickly become very interested in topographical surveying. In Britain they create a government department literally called the Ordnance (cannon) Survey, which still makes large-scale maps today. In France they create a library of relief maps to delight the heart of any minis wargamer:

Vauban gets commissions to redesign a ton of towns in France and on its borders – in particular, Louis has a grudge against the Duchy of Savoy, down in the Alps, which is (a) Protestant and (b) smells vaguely Italian. So he sets out to conquer it and gets Vauban to make it defensible, with mixed results. Embrun, in particular, Vauban called “unfortifiable, hopeless.”

So Louis has him build another town down the road – Mont-Dauphin – so he can starve Embrun of all trade and income. But nobody moves in, and Vauban’s boring town plan gets blamed.

Vauban’s last work is the whole town of Neuf Brisach. inner enceinte de sûreté, the bastion wall around the city,

and an outer enceinte de combat, a system of concentric star-shaped earthworks.

Vauban’s influence survives his death, despite engineers slowly improving artillery through the 18th century, until an artilleryman becomes emperor of France in 1804, when France suddenly adopts explosive shells and starts expanding again.

Cherbourg, Brittany, refortified 1810

So out of this, what are the useful lessons for game designers?

1. Defenses evolve symbiotically with modes of attack: each develops to take advantage of the other’s weaknesses. So. If you have fireball-wizards or intelligent swarms of rats, what are the affordances and weaknesses of those attack modes?
2. But that evolution doesn’t happen overnight. It can take years for an idea to travel across a cultural divide. If the Ottomans had mounted a serious attack against England in the 1530s, they would’ve found the place unready for the same cannons with which they attacked Greece in the 1330s.
3. Everything we build is cultural first, functional second: we tend to think of functional design as the simple operation of cleverness in solving problems – what will work to achieve the desired result? – but functionalism always has culture behind it. What results are desired and why? Why is it necessary to fortify this place in particular? And important functions always get expressed in other ways, culturally. So what art, what values, what other fields of endeavour get tied up with your military interests?
4. People will go to enormous lengths to defend their stuff… sometimes their defensive works are much more expensive than the things they’re defending. There’s a danger here for the defenders, though: the more they invest in one mode of defense, the less they want to switch to another mode. France continued the ruinously expensive practice of Vaubanizing their cities long after the guns they were defending against had been replaced by new ones that Vauban never anticipated. People who are familiar with the history of the Maginot line are probably shaking their heads right now. But that same impulse, to get ready to fight the previous war rather than the current or next one, keeps cropping up throughout history. So
5. The devil you know may have already been replaced.