How would castles be designed in a world where magic exists. Magic has the following rules:

  1. All magic requires runes and a verbal activation (saying 'magic words' that correspond to the runes)
  2. Any spell lasts a maximum of one minute (no enchanting)
  3. Any spell has a certain maximum amount of power, and will not complete tasks under that power (you can create a small fireball, but can't make a storm or teleport)
  4. Any spell takes three seconds to take effect after the verbal component has been said (gives time for a counter-spell)
  5. Runes can be traced on a surface (temporary rune) and can then be activated only by the maker, or engraved/written (permanent rune) where they can be triggered by anyone holding the object.
  6. All activation phrases must be yelled, and cannot be muffled (can't use magic while gagged or holding cloth over face)

I want to know how castles would probably be designed, given that this type of magic exists, and is fairly accessible, although normal troops would likely only know a few spells, mages who know thousands would accompany every army and defend every fortress.

Magical firearms don't exist yet (no one invented them at this point) but magical self-loading crossbows have been invented and are common, although loading a trebuchet is out of the reach of a single spell.

  • 1
    $\begingroup$ this is only going to be limited by the creativity of the builder and the limits of the magic, even something as simple as whether magic can be used to fly or float will make a huge difference. $\endgroup$
    – John
    Mar 18, 2017 at 1:50
  • 1
    $\begingroup$ Sorry, but magic isn't quite powerful enough for flight. Fireballs work, and in combat the spell 'die' is usually pretty effective. \ $\endgroup$
    – Gryphon
    Mar 18, 2017 at 2:13
  • $\begingroup$ I think on castles you understand essentially fortresses, i.e. with the purpose to defend a territory against invading armies? $\endgroup$
    – Gray Sheep
    Mar 18, 2017 at 3:28
  • $\begingroup$ What about illusions, do they exist in your world? And necromancy? Divination? Sorry I can think only in the d&d framework. $\endgroup$
    – Gray Sheep
    Mar 18, 2017 at 3:29
  • 1
    $\begingroup$ Yes, fortresses to protect territory/provide shelter for citizens. Necro is too powerful, divination can only be used close by (5-10 kilometers) and you have to specify a location, not a person or animal or that kind of thing. You can check fairly well for an ambush at a specific location though. $\endgroup$
    – Gryphon
    Mar 18, 2017 at 3:40

3 Answers 3


Physically, castle would be designed just like castle in our world. I'm going to assume runes will be depleted after the spell activate.

The bricks on walls and towers will be inscribed with defensive runes, should a siege or attack begins. These will serve as emergency defense until the runes run out, and the defense must be resupplied with defensive scrolls. (Think of them as 'defensive bullets')

Magical warfare should primarily fought with supply of scrolls - an inexpensive and portable rune-holder.

There will be physical weapons ready, too, but mostly how they use weapons to defend will be similar to ours, with a slight twist (like auto-reloading crossbow) - though I think this is should be considered temporary enchantment.

Depending on the system, what kind of spell and the extend of the power allowed, this could only be a fireball-frostbolt-lightning bolt throwing magical warfare.


Just saw this, so I apologize if it's too late to be helpful.

Here is my two cents:

  1. If a rune can be made permanent (but must be utilized as by speaking a clear verbal command) then I would assume a castle would be full of such runes
  2. Additionally, if there is nothing in the magic system that disallows runes above a certain size, then I would think clever castle builders would shape the castle and/or components of the castle, in the shape of a rune... (so each section of the wall could be in the shape of a rune, or the entire outer wall of the castle could be a rune, and the inner wall a different one etc...).
  3. If there is nothing in the magic system that prevents it then a series of runes in a given order may provide specific benefits when cast together (I suppose timing would be important here but could be another skill of mages & workers of magical machines)

DETAILED BENEFITS of the above points

  1. Putting runes on everything: defensive & where appropriate and useful for defenders, defensive runes would be beneficial to fend off various attacks, and offensive runes to launch attacks as needed during a siege. e.g.
    - A defender is atop the primary castle wall, he and the defenders around him see a catapult being fired & it appears to be toward their section of the wall, they all yell the appropriate command and activate the defensive runes within the sounds of their voices making the wall impregnable for 3 minutes, the boulder shatters harmlessly against the defended wall.
    -In another instance a small group of defenders man a section of the wall that has 50 fireball runes with the stone blocks they are carved on all pointing to a certain spot that the attackers are moving their battering ram through. These defenders all yell the appropriate activation word and 50 fireballs rain down on the spot currently occupied by the battering ram and it's handlers...
  2. If the castle walls are formed in the shape of a rune, then any defender can activate that rune when needed to gain whatever effect is granted by said rune. Therefore a few defenders could potentially more easily defend against a larger number of attackers. Additionally if size (mass of material used etc...) affected the power of the rune, then a meter thick wall encircling an entire castle would make for a seriously powerful affect... (this could allow for fireball cannons being created out of big blocks of steel or stone with the rune on one side...)
    One additional thought here, what would happen if a wall were in the shape of a defense rune and that same defense rune were carved all over that wall... when activated would the runes act as multipliers to each other?
  3. Runes could be used to make sounds, and therefore words and sentences. Therefore one rune could be used to activate other runes that could be used to activate more etc...
    I could see a scenario where a wizards keep could be lined with 'message' runes which would be used to remotely mass activate all the runes on the keep... or a specific area of the keep. This would allow a single person to fend off a large army (or @ least have a better chance @ it).
    Another use for this would be creating the capability of producing very complicated effects... add some fire, add some wind, then some water and make it repeat every 3 minutes (a physical loop would have to be pretty large but it would be possible) and fog could be generated. (or put a series of fire runes that are set in a loop that would fire itself every 3 minutes inside a moat to create steam & fog for defense (and maybe to protect against flame attacks etc...)

Hope these ideas are helpful.

  • 1
    $\begingroup$ +1 for making the castle in the shape of a rune, that was Arlen's idea in The Warded Man, don't just ward the castle use the castle to ward the entire countryside. $\endgroup$
    – John
    Nov 4, 2018 at 14:28

If you are able to engrave especially anti-magic, but any defensive, runes into the castle itself then the design of the castle would be entirely equivalent to that of the other weapon technology; though given your comment battle management from the towers would become important for the mages to see and quickly counter-act against incoming spells.

If the fireballs are just surface explosions then again the castle design wouldn't change much; measures to prevent the spread of fire perhaps. Castles are already designed to prevent damage from incoming projectiles. The Hordings would have to be fire-proof though.

If the fireballs have some amount of penetrating power on the walls than they can be viewed as cannons and, depending on the effectiveness, would change the castle walls to being Bastions or star fortresses or even later designs.

  • 1
    $\begingroup$ Magic requires words to activate, but it might be possible to magically shoot down many approaching projectiles, however anti-magic or defensive runes still require a guy to say the activation spell (quick thinking is a vital attribute for mages). Fireballs aren't really effective enough to be considered cannons but there needs to be some way of protecting soldiers from incoming fire/ice/electricity/etc. balls. $\endgroup$
    – Gryphon
    Mar 18, 2017 at 3:37
  • 1
    $\begingroup$ @Gryphon: "Magic requires words to activate" - do these words have to be spoken by a person, though, or can the magic also be activated by sound-producing runes or whatnot? $\endgroup$
    – Vikki
    Apr 2, 2020 at 20:23

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .