Can sieges withstand magical assault?

[painandgreed]

It is easier for magic to destroy things then to create things, so the people attacking would be able to eventually destry the walls and get in.

Ok, but with the time and effort that it took the attackers to destroy the walls and get in, they've been at a disadvantage and have lost more people given that the defenders are busy using their magic to destroy the attackers. By time the defences are ruined to the point that they offer no advantage, the forces would no longer be equal because the attackers would have suffered more losses than the defender.

A major point of such defences are bottlenecks. Walls are there but most castles are placed in hard to reach places where the gate is the only approachable route, walls or not. Tus the point of attack is often known unless the attackers undergo serious effort to mine or build up approaches such as at Masada. The attackers will be botlenecked in these areas or any they create and packed into a small area while the defenders will be able to spread out more along walls or even different levels of the fortifications. This would highly favor the defenders while using magic to detroy each other.

 

[Evilhalfling]

I would certainly give the edge to the attackers,
The defenders cannot be prept every hour of the day, but the defenders can choose the time and place of the attack. Invsible flying and teleporting attackers have a tremendous advantage.

Defenders can block such things but it is very expensive to set up standing magial defenses
I give a few pricebreaks, and make it a little easier, but castles are not really set up from arieal attackers.

 

[drnuncheon]

I think your answer is going to vary depending on the magic.

If it is 'rare, but powerful' then the siege will go to whoever has the wizard, and wizards of equal power will largely counter each other - there's only so much a single caster can do. The beseiger might cast cloudkill, but the defender's gust of wind disperses it. The beseiger disintegrates a wall but the defender's wall of stone seals the gap.

If it is 'common', as in most or all soldiers have some, then you'll see the widespread changes as squads of spider climbing troops head over the walls, with overland flight "bombers" dropping spheres from a necklace of fireballs, etc.

J

 

[Darkness]

I would certainly give the edge to the attackers,
The defenders cannot be prept every hour of the day, but the defenders can choose the time and place of the attack. Invsible flying and teleporting attackers have a tremendous advantage.

And the defenders can attack the attackers' camp in the same way, except even more easily.

 

[barsoomcore]

I think in a magic world, the very definition of a "castle" is going to be different. Big walls of stone are probably pointless to build -- they aren't going to defend you against anything very dangerous, and you can probably build much more effective defensive systems that consume less labour (more wealth, but you only have to pay that once, right?).

Wizards would almost certainly become siege specialists, just like engineers did in medieval times, and would develop spells and materials and methods to build powerful fortresses that could resist all kinds of attacks. The most powerful and most wealthy rulers in the land would hire these people to build them fortresses (or, much more likely, these people would build their own fortresses and take over).

The basic notion of a seige in a world containing non-resource-consuming food and water is pretty much nonsense, but then so are castles, guys with swords and a host of other conventions we like because they're cool. I mean, if those good gods are so good, why don't they give EVERYONE IN THE WORLD create food and water EVERYDAY? Ninety percent of all conflict and suffering in the world would be wiped out.

Whoops, ranting. Never mind.

 

[Evilhalfling]

And the defenders can attack the attackers' camp in the same way, except even more easily.

The Attackers don't have to be anywhere near the castle before attacking. I guess I am assuming ninja type raids to kill off the highlevel defenders, and then troops to mop up.

 

[rounser]

Every spell used on the fortification is one less spell used on the defenders themselves....and disintegrate meets it's match with wall of stone. ("What do you mean the wall's getting thicker?")

 

[Hitokiri]

Ok, Im going to run a few scenarios methink this weekend and see what happens, but here is my current thoughts.

1) many have emphasized ways attackers can bypass the walls using magic. Most of these can be safeguarded against magically, but would be VERY expensive. However, castles in and of themselves are expensive projects, adding in the cost of some magical protections may not seem so bad by comparison. Additionally, hiring a mage good enough to give you an army of invisible flying attackers will be JUST as prohibitively expensive, so I feel the cost question is moot.

2) Assuming parity of firepower, both mundane and magical, what is to prevent the defenders from staying hidden behind their walls and waiting for the attackers to waste spells bypassing them. Yes, a mage may be able to disintigrate a section of wall and send in a bunch of invisible troops that have been enhanced. However, he is now down key spells, while the defending mage is still at full power and can deal with the troops as they enter the breach. My point is that the walls force a depletion of magical ability from the attackers, who will not have any real advantage just because they have breached the walls (they will have mearly NEGATED the advantage the walls gave the defenders). Even disregarding the fact that even once the walls are overrun, the defenders can use ambush tactics and known terrain to give themselves an advantage, the disparity between the available magical firepower between the two forces now gives the defenders an advantage (whether or not it is as large as the original wall advantage could be argues, but the defender still lokos to be in the better position).

Assuming parity of force, I can not see any way that anyone can give a definative edge to the attackers. To do so, one would have to claim that having a fortified position is somehow a liability (or that attacking such a position is an advantage).

edit:
As for "ninja" style raids, castles are not set up for this type of conflict. But I somehow don't see groups of high level adventures (which would have to be the case to pull this off) generally being available to do this type of work, at least once again not at anything resembling a "reasonable" fee. If your thought is "can a castle stand up to a group of high-epic level PCs" then I would answer most likely not. But then again, the same could be said for most anything.

 

[argo]

Well, lets look at what happened to castles in the real world. When the cannon was first introduced it did not mean the immediate end of massive defensive positions, instead castles changed and adapted to the new weapons while sieges focused on slowly approaching the walls under cover (trenches) to attack at point blank range. The outcome was much the same as before: a castle besieged by superior forces with no relief will fall given enough time.

But castles did eventually go out of style. Once fierarms became plentiful enough and portable enough governments eventualy decided that it was better to mantain a standing army (which can also be used in attack as well as defense) and try to take the initative away from the enemy by meeting him in battle at a place of your choosing to destroy him. Now stationary defenses are used mostly to protect the most vital locations and to control the shape of large scale manuvers: force the enemy to approach your country from a particular angle or suffer the ranged fire of your castle battery.

Then we get to modern warfare and two factors make all static defenses, even fire-support batteries, useless. The first is mobility, the power to either close on your defenses and overwhelm them before they have time to prepare or else to bypass them and attack from the rear or attack the command/supply centers. The second is the overwhelming power of offensive weapons: no castle design could withstand a sustained high-level bombing let alone a singel nuke.


Since there is no problem in standard DnD with the portability of magic I think it comes down to how plentiful the magic is. If all we are talking about is a lot of 3rd and a few 4th level spells then I think you could build castles that adapt to that level of force and sieges would just have a lot of additional fireworks. However, if we are talking about spells of about 6th level or higher then the attackers are going to start having a massive advantage in terms of mobility and firepower. Even if the defenders have equal magic it isn't going to do them much good against "bombing raids" unless they want to go out and hunt the mage and then we are back to open field fighting again. So yes, I do think that there comes a point where static defenses become less cost-effective than a well equiped standing military and that is the point when castles will start to dissapear.

Of course none of this mentions stealth attacks, but I guess that is where the king goes out and hires a party of adventurers right?

Later.

 

[Andre]

Well, let's break this down a bit and see what happens:

1. No magic on either side. So long as the attacker can enforce a siege long enough, the defenders lose. Eventually starvation or disease will defeat them.

2. Moderate magic on both sides. This is trickier. If we assume the attackers have enough resources to form strike teams capable of getting into the castle and raising havoc, we assume the defenders can do the same to the attacking army. My guess: victory goes to the side that uses the best tactics.

3. High magic on both sides. No question - just like combat with high-level parties, victory will likely go to the side that gets in its punches first. If the attacker can choose the time of its attack, it will likely win. If the defenders can ambush the attacking army while it's travelling, they'll have the advantage.

Note, none of these scenarios requires modifying the castle itself. This is for two reasons. One, as others have pointed out, strong defenses against magic covering an entire fortress are prohibitively expensive. As the French learned with the Maginot Line, that money would probably be better spent on some strong, mobile, offensive forces instead. Two, protecting a fortress against an army with magic is only part of the problem. What about dragons? Beholders? Demons and devils? You can't cover everything. Likely a fantasy castle would serve the same purpose as our real-world ones: control an area against mundane threats, which are also the most common. Stopping the more powerful magical threats is what cannon-fodder...er, I mean adventurers...are for.