Medieval Castles & Knights: Secrets Inside the Walls

Nova: Buckle up, Explorers.

Cosmo: Brains in!

Nova: Wheels up!

Nova & Cosmo: Brain Bus, let's GO!

Nova: Welcome to The Brain Bus - I'm Nova, your driver, and my robot co-pilot Cosmo and I have been waiting all week to take you here. Right now the Bus is phasing us straight into the Middle Ages - because I need to tell you something about castle toilets.

Cosmo: Oh, here we go.

Nova: The toilet in a medieval castle - called a garderobe - dropped waste straight down the outside wall. No plumbing. Just gravity and the outside air. And people hung their fanciest, most expensive clothes right next to it. On purpose.

Cosmo: On purpose?!

Nova: On purpose! Because the smell was thought to keep moths away from the fabric. The "bathroom" was also the wardrobe. That is a real sentence I just said.

Cosmo: This trip already smells amazing.

Nova: Everything about a medieval castle turns out to be stranger, cleverer, and grosser than you'd expect. Let's go in.

Nova: So here's the big idea for today, Explorers. A castle is basically a suit of armor - but turned into a building big enough for a whole town to live inside. Just like a helmet protects your head and a shield covers your body, every single part of a castle - the walls, the ditch, the weird little windows - protects something too.

Cosmo: Speaking of armor - Nova, I have it on good authority from my Space Guidebook that knights were basically walking fridges. So heavy in all that metal that they needed a crane to lift them onto their horses.

Nova: Oh, Cosmo.

Cosmo: A crane, Nova. A proper crane.

Nova: That is a famous movie myth, and it is beautifully, completely wrong. A full suit of battle armor weighed only about twenty kilograms - spread across your shoulders, hips, arms, and legs, like wearing a very heavy backpack distributed over your whole body. A fit, trained knight could run, climb ladders, and leap straight up into the saddle himself.

Cosmo: Twenty kilograms. That's... a lot of bags of flour, but spread out. Okay. I can see that.

Nova: And knights trained from age seven to get used to it. You started as a page - basically the lord's apprentice kid - then at around fourteen you became a squire, and if you were good enough, you were knighted around twenty-one. That's fourteen years of training before you got the sword tap on the shoulder.

Cosmo: Seven years old! That's like starting to learn full-contact chess.

Nova: On horseback. And speaking of horses - a knight's trained warhorse, called a destrier, was so valuable it could cost more than all his armor and weapons combined.

Cosmo: The horse was the expensive bit?

Nova: The horse was the very expensive bit. Now - let's look at the castle itself, because every feature is doing a job.

Nova: Look at the moat - the wide ditch of water around the outside. Explorers, what do you think a moat was actually for?

Cosmo: Keeping out swimmers?

Nova: Wrong, but a good guess. The moat's main job was underground. If attackers tried to dig a tunnel under the walls to collapse them, the moment they got close - the water would pour straight into their tunnel. The moat was defending the castle from below.

Cosmo: The moat was lying in wait. That's sneaky. I respect it.

Nova: Now look up. See those walls? Many castles weren't grey at all. Builders coated them in white plaster or limewash so they gleamed across the landscape for miles - half fortress, half enormous billboard screaming "a very powerful, very rich family lives here." Bright white. Blazing.

Cosmo: Wait. I said castles were cold, damp, grey piles of boring stone.

Nova: You did, about thirty seconds ago in your head, and you are incorrect.

Cosmo: The Space Guidebook has let me down again.

Nova: Now, look at those narrow window slots in the walls - arrow slits. They are narrow on the outside and wide on the inside. That shape means an archer inside has a big wide opening to swing his bow and aim in lots of directions, but the enemy outside has an almost impossibly tiny target to hit back. One clever shape, two problems solved at once.

Cosmo: It's like - it's like a really aggressive cracker! Someone took the cracker wall - wait, no, I'm looking at the TOP of the wall. Those up-and-down teeth along the battlements. Who took bites out of a giant cracker?

Nova: Those "bites" are called crenellations - the gaps let soldiers shoot arrows, then duck behind the solid bits. Every nibble has a job.

Cosmo: I'm calling them the cracker-top and no one can stop me.

Nova: And at the gate - that massive iron-and-wood grid that crashes straight down to seal the entrance?

Cosmo: The portcullis! Which I am choosing not to rename as a waffle iron, because I am a professional.

Nova: It had death holes in the ceiling above it, so defenders could pour things down on anyone trapped underneath.

Cosmo: Okay, "death holes" is already a better name than anything I would have come up with.

Nova: The defenders threw things that could hurt attackers by slipping through the gaps in their armor. The castle's whole entrance was a trap.

Nova: And in battle - how did you tell your own knights apart from the enemy when everyone's face was hidden inside a helmet? Each knight had a unique pattern painted on his shield and sewn onto his tunic - a coat of arms. Your family's symbol, visible from across a battlefield.

Cosmo: So the coat of arms was basically a username.

Nova: A very well-armed username, yes.

Nova: One more - jousting lances were built to shatter on impact. That was the design. The lance breaking spread out the force of the collision, which helped keep the rider safer. Which means the whole dramatic CRACK of a joust wasn't a failure - it was the point.

Nova: Okay, Explorers. Just stop for a second here.

Nova: Every single thing we've looked at - the garderobe smell, the moat's hidden job, the arrow slit's shape, the shattering lance - none of it is an accident. Castles look the way they look because the shape of a building tells you exactly what it was built to do. When something seems strange, ask: what job is this shape doing? That question works on castles. It works on bridges. It works on animals. It works on almost everything.

Nova: The strangest designs are usually the smartest ones.

Cosmo: I'm going to look at parking garages differently now.

Nova: You absolutely should.

Nova: And here's something worth sitting with, Explorers - the same arms race has been running for all of human history. Attackers built trebuchets to throw things farther; defenders built thicker walls. Defenders built thicker walls; attackers dug tunnels. Every clever attack demanded a cleverer defence. Castles are a frozen record of that conversation - stone evidence of a problem and its solution, layered on top of each other for centuries.

Cosmo: Attack. Defend. Invent. Attack again.

Nova: That's the whole story, really.

Nova: Quiz time, Explorers! Three questions - Cosmo and I are competing, and so are you. Shout your answer out loud.

Nova: Question one. True or false: knights were so heavy in their armor they needed a crane to get onto their horse.

Nova: False! Armor was about twenty kilograms spread across the whole body - a trained knight could climb on himself.

Cosmo: I got that one right. Eventually.

Nova: Question two. What was a medieval castle toilet called? Was it (a) a garderobe, (b) a throne room, or (c) the splash hall?

Nova: It's (a) - a garderobe! And it doubled as a wardrobe, because the ammonia smell kept moths off the clothes.

Cosmo: The splash hall was my personal favourite answer.

Nova: Question three. About how old was a boy when he first started training to become a knight - about seven, about twelve, or about eighteen?

Nova: About seven! Because fighting in full armor on a galloping horse takes as long to learn as any serious sport - you needed all those years.

Cosmo: Seven! That's basically a professional career starting in second grade.

Nova: However many you got, Explorers - the fact that you were thinking hard about every single one means your brain is doing exactly what we brought you here for. That's the whole win.

Nova: Fun Fact Blast - four rapid-fire facts you haven't heard yet today. Cosmo, ready?

Cosmo: Data Log open, pencils out.

Nova: One! Attackers sometimes loaded their trebuchets - giant counterweight catapults - with dead animals or diseased bodies and flung them over the castle walls. They didn't understand germs yet, but they'd noticed that this made the people inside too sick to keep fighting. It was the world's first, nastiest germ warfare.

Cosmo: Medieval science: extremely grim, surprisingly logical.

Nova: Two! Some castle spiral staircases twist clockwise going upward, and some historians think it was deliberate - a right-handed defender coming down has more room to swing his sword, while the attacker coming up is cramped. Historians are still arguing about whether it was truly on purpose, but it is a fact that the twist existed and that it helped defenders.

Cosmo: The staircase itself was a weapon.

Nova: Three! Jousting lances were engineered to shatter - wait, I said that one. Okay - three: castle walls could be several metres thick. Thicker than a grown adult is tall. Solid stone all the way through. Not a thin shell - a mountain you built yourself.

Cosmo: You're not walking through that wall. You're not even thinking about it.

Nova: And four - this one comes straight from the Data Log. Cosmo?

Cosmo: Filed under: arms races. First entry. Every attack creates a new defence, which creates a newer attack. We saw it with T. Rex's jaws against its prey's defences - bigger teeth, faster prey, bigger teeth again. Castle walls got thicker, so trebuchets got bigger, so walls got doubled into concentric rings. It's the same escalating game, millions of years apart. Filed.

Nova: I love that connection.

Nova: Alright Explorers, Road Challenge - and this one works entirely in your head, no looking around required.

Nova: You are the royal castle designer. Attackers are marching toward your gate right now. Walk from the outside in and build one defence at each step. First - what slows them down out in the open, before they even reach the wall? Then - what stops them at the wall itself? And then - what's waiting for them at the one doorway into the castle?

Nova: Three layers, three different jobs. Build it in your head. You can talk it through with everyone in the car - there's no single right answer, just good engineering thinking.

Nova: Now - wondering question for the whole family.

Nova: What's a building we have today that's designed to keep something safe - a bank, a vault, a server room, a museum - and what clever tricks does it use instead of moats and walls? Are those tricks really so different?

Nova: Before we phase back, Explorers - the Next-Stop Riddle. Listen carefully.

Nova: I hang above the gateway, heavy, cold, and mean.

Nova: I've got rows of iron teeth, but I never need to clean.

Nova: I come crashing down so no enemy gets through -

Nova: What am I?

Nova: Hold onto that one - we'll come back to it.

Nova: But here's your real riddle for next time. Something else travels the world, goes by many names, lives by its own code of rules - part history, part legend, part terrifying truth. People think they know what it is. They're about half right.

Nova: What is it? You'll find out next time on The Brain Bus.

Nova: Explorers, today we walked into a building that was also a machine - a machine built entirely out of problems and solutions, stacked in stone. Every smelly garderobe, every white-painted wall, every too-narrow window was someone's very clever answer to a very dangerous question. Keep asking those questions about everything you see.

Nova: Stay curious, stay clever, and keep that brain working!

Nova: Until the next stop, Explorers...

Cosmo: ...keep wondering.