Take the 2-minute tour ×
History Stack Exchange is a question and answer site for historians and history buffs. It's 100% free, no registration required.

Castles were designed to hold people, weapons, and supplies to survive a siege. They were well-defended. Taking one could easily be a long, bloody struggle.

Why attack at all? Most castles I've seen could be trivially circumnavigated. The resident soldiers would have to come out to attack, bringing the conflict into the open and away from traps.

Why didn't armies simply ignore castles and go around?

Are there any examples of this approach succeeding or failing? i.e. was the belief that castles are worthwhile based more on experience or imagination?

share|improve this question
3  
I feel this question is too broad as it is. Would you like to narrow it to a specific battle/siege or war? In general, though, you wouldn't want to leave a castle of hostile enemies behind you, ready to cut you off. You'd also have to take the castle if you want to effectively control the land it commands. But there are a whole host of different scenarios. –  Semaphore Jun 26 at 13:26
1  
Supply lines. And control. Armies exist to fulfill a strategic objective. You only build castles where they will inhibit the opponent's ability to fulfill his strategic objectives. Also, you tend to strip the countryside to stock the castle, leaving nothing for the opponent's army to eat. –  Mark C. Wallace Jun 26 at 13:40
1  
@Semaphore can you please justify "you'd also have to take the castle if you want to effectively control the land it commands"? I see no reason at all why this should be so. –  spraff Jun 26 at 13:47
10  
Your premise seems to be that if an enemy garrison sallied, it will never do so in such a way that put your forces in a bad situation (e.g. attacking supply routes or you from behind while you are facing off another army). This led to your faulty conclusion that hostile castles don't need to be taken. –  Semaphore Jun 26 at 14:03
2  
The answer to the question "Why bother attacking castles at all?" is a fairly simple one: If the attackers want to own the castle they first need to evict the current owners. –  apaul34208 Jun 26 at 22:11

8 Answers 8

up vote 27 down vote accepted

Armies go around castles all the time, but what usually happens is that the castle is placed under siege. This is done at least with the intention of keeping the defenders in, and hopefully taking the castle via attrition, bombardment, sapping or treachery.

The need to siege the castle is important; if you ignore the castle and march on, this leaves the rear of your army - and worse, your supply line - highly vulnerable to attack by the defenders sallying forth. There are few examples of this happening because ignoring castles without besieging them is a huge tactical blunder.

So why have castles if the attacker can just siege them? Because sieges are very expensive to do. Manning a perimeter is obviously going to take more manpower than manning an isolated strongpoint - the Art of War quotes a tenfold requirement in men, which although not a hard rule, gives you some idea of the scope of the problem. Also it is very likely that this siege is being done in enemy territory, giving the defenders an interior lines advantage. Also, castles tend to be well-stocked with supplies, so that even without resupply, they can often last months, sometimes even years. Take a look at this list of sieges; there are many examples of ones lasting more than one year. With the defenders able to maintain such a huge logistical advantage for a very long time, how can you not see how awesome castles are?

This is also why castles are sometimes assaulted, despite the huge tactical disadvantage: the attackers simply cannot afford to tie up so much of their forces in a siege, or continue supplying them through enemy territory for so long. Ignoring the defenders risks the rest of the army coming under attack at their weakest positions.

Hannibal's invasion of Italy during the Second Punic War shows some of these dynamics at play:

  • Despite invading from the north, Hannibal bypassed Rome to take most of southern Italy
  • He did not really besiege Rome (but being one of the best generals in history, he had good reasons for this). This enabled Fabius to undertake his famous eponymous strategy: unable to best the Carthaginians in pitched battle, he used small, mobile forces to endlessly harass Hannibal in the rear.
  • In the end, although numerically matching the Romans and outmatching them in most battles, Hannibal could not overcome the tremendous home front advantage the Romans had.
share|improve this answer
5  
This continued/continues even to the present day. The US Army creted firebases in Vietnam. Like castles, these were fortified areas where they could put headquarters and artillery to support troops in the field. The NVA could have simply bypassed them and attacked wherever, however the troops within would continue to harrass. So the NVA would attack the firebases, with overwhelming numbers, in order to destroy them, removing the support they would provide troops in the field. IMO, the concept is similar to castle sieges. –  CGCampbell Jun 27 at 14:30
    
There is a flaw in your argument for your need for siege; Supply lines where not a thing before the 17th century. Armies carried their supply in their supply train, which traveled with the army. –  Taemyr Jun 30 at 8:01
    
@Taemyr Not exactly. Supply trains were mostly quite limited in medieval times, and the army usually lived off the ground, foraging. And that's quite hard to do when your army isn't on the move. Given that many walled cities and castles had enough supplies to last for years, a wait-them-out siege was often out of the option, even if just because you needed those men in your army to go back to your fields to produce. True, it did change somewhat when standing armies again began to be the standard as opposed to levies, but it was still tricky maintaining an army for more than a few months. –  Luaan Jun 30 at 11:45
    
@Luaan True, I was inaccurate. I meant that supplies that had to come from home was carried in the train. In either case, for foraging or for train, there is no supply line to worry about. –  Taemyr Jun 30 at 11:47
    
@Taemyr Yeah. That said, if you needed supply lines from home, it would become an extremely costly affair. Unless your army was actually designed around that, the way the Romans or Chinese had it. Which basically meant that as soon as your supplies run out and you had nothing left to forage, you had to move on. –  Luaan Jun 30 at 11:54

There are two assumptions that need to be clarified.

  1. What is the attacker's strategic intent?
  2. What time are you talking about?

If the attacker wants to possess the territory defended by the castle, then "going around" isn't an option. "Going around" only makes sense if the attacker wants to control territory beyond the castle.

This also assumes that the defender isn't stupid—the defender has placed the castle to inhibit the attacker. Either the castle is placed to control a strategic point (See @user5088's answer), or the castle is part of a network (English castles on the border of Wales, or English fortifications on the southern coast to protect against Napoleon). If the defender is clever, the castle is positioned in a way so that "going around" the castle exposes the supply line, and if the defender is really clever, then the castle is situated so that the attacker cannot avoid the castle.

The original castles (motte and bailey) were really only intended to protect the inhabitants of the local region. When raiders attacked, the population retreated within the castle with their goods. The attacker certainly could go around.

Later castles were designed as strategic reserves. Everything valuable (people, crops, animals, chattel, etc.) were withdrawn within the castle. That means that the attacker can't just go around the castle, the attacker has to go around the entire cultivated area—because the defender has laid waste to the territory. If you can't bring it in the castle, burn it. Foraging is very expensive—even up until the US Revolutionary war, foraging determined whether the army could survive in the field.

The attacker's only option was to carry all supplies (food, ammunition, replacement stocks & stores, animals, feed for draft animals, etc.). The supply train consumes supplies as well as carrying them—every mile that the defender can extend the supply lines is more expensive for the attacker. And every mile that the defender can force the supply train to travel makes it exponentially more expensive to protect that supply train against sallies by the defender.

share|improve this answer
4  
I'm not sure if this is embodied in your answer already, but I feel a more detailed description is justified. Japanese castles are huge. They wall off what seems like miles of terrain, and they have highly defensible structures scattered all throughout. One of the walls is usually right on a river, and the river is somehow played into the design. I always felt the massive area covered was a weakness, but perhaps it's made up for by the capacity to sustain an army inside. The walls themselves are always pretty intimidating, and the layout reveals terrifying ambush points. So, +1. –  Wolfpack'08 Jun 28 at 11:47

There are at least two reasons. The first is that a castle is usually located on the most strategic ground in the area, a hill, river, etc. Basically, it is, or controls, the most valuable "real estate' in the region. If an attacking army controls the "rest of the region" without controlling the castle, it hasn't achieved much.

The second reason is that the castle contains the enemy army. Capturing the castle means capturing the opposing army, and thus winning the war. If an attacker leaves the opposing army at large while it goes about is business, it becomes a "free for all," anything can happen, not all of them good for the attacker.

There are times when bypassing the castle is a good strategy. That is when the castle has no inherent value and the surrounding territory is much more valuable. But that's the exception, not the rule.

share|improve this answer
2  
Not only the enemy army was in the castle, but the enemy himself. Such people were contenders for (or were actually) the crown. To defend the crown or to take it, you have to defeat that person. –  andy256 Jun 27 at 11:07
    
@andy256: Enemey armies are accompanied by enemy leaders. It's a rare (and foolish) leader that's not with his strongest army. One advantage of a siege is that the enemy leader is isolated and can't communicate with the relief forces; as the Romans and Gauls found out at Alesia. –  Tom Au Jun 28 at 17:30

Spraff, you aren't considering why the castle is placed where it is. Does it control a ford or landing point? Does it guard the best passage through a hill/mountain range?

The placement of the castle is why it exists in the first place; they're built at strategic locations which forces the enemy into either attacking or besieging them.

share|improve this answer
1  
This does not provide an answer to the question. To critique or request clarification from an author, leave a comment below their post. –  Kobunite Jun 27 at 18:17

Because they're the goal

Go around castles to where exactly?

Military campaigns usually have some goal in mind - typical goals include (a) conquering territory; (b) robbing wealth; (c) long-term damage to an enemy. Achieving these goals requires taking the castles - in earlier times, most of important people, wealth and military force would be moved inside the castle walls; so going around the castle would make the war pointless, you'd do some pillaging but not gain much.

In the time period where castles are important, burning the part of city that's outside the walls isn't critical damage, all the important things were crammed inside the castle/city walls.

Because you want the armies to stay there

If you go around them, then you're not "forcing a conflict in the open" since by definition you're not there anymore. The smaller enemy force that didn't want to fight you on field, can now avoid you because left, and once you're a long way off, they're free to do everything else - merge with other forces to fight you later; evacuate wealth; invade your lands; etc. If you leave behind a siege force, then you pin them down and prevent them from taking action.

share|improve this answer

A lot of the main reasons have already been mentioned, such as supplies, strategy (you wouldn't want to leave an enemy behind you etc) and the fact that you can setup base if you overtake it - allowing you to push forward. It would have been a strategic move to put the castle there in the first place, so being able to have that advantage is worth it.

Another reason is to get to the people inside - kill an enemy supporter / a person with power. Castles would be owned by nobility and therefor worth bringing down. In that way, you gain control of the land and the people. If you were to just pass by, you gain nothing.

What you say about luring people out into the open did happen (e.g. The Battle of Wakefield). Richard, Duke of York made that mistake and was killed.

It's hard to answer the question without knowing why the castle was there in the first place and why the army was attacking. Open land would be easier to take over, but would you leave valuable things unprotected? If it's not the land, then it's what's inside the castle - usually people. Why would you send an army out there in the first place if not to attack - if there is going to be a fight, then it's better on their doorstep than yours.

share|improve this answer

Most often, it would be related to supply - castles will often overlook or block roads or passes. An army requires a vast amount of food and other supplies, which can either be brought by wagon from 'home' or taken from your enemies (and thus it's likely stored in the castle).

A large army might be able to walk around a castle, but then when the army has passed, no wagons can follow behind them. A army without a supply line is a useless army.

share|improve this answer

If we talk about those small castles on hilltops which (or their ruins) can be found all over mainland Europe, it's important to first understand what their purpose was. We are not talking about early medieval castles which were just protecting the property of a single family, but military installations of late medieval to early modern Europe.

So, what purpose did such small castles (most of which couldn't hold more than a few hundred defenders) have in the face of an army of tens of thousands? They are obviously not the goal of a campaign, they are not the fortified cities which would be valuable for the attacker.

What does the attacker want? They want to besiege an important city or the capital, or force a decisive battle with their opponents so they can sue for an advantageous peace. They arrive to a tiny little fortress which sits on a hilltop. What would you do?

  1. You storm it. You have tens of thousands of men, they have at most a few hundred. However, due to the strategic position and construction of the castle, storming it would be very costly. In the few cases an army in a hurry did do it, it was not uncommon to suffer ten times (or much more) casualties than the defenders. It would almost always be a Pyhrric victory.

  2. You besiege it. You start bombarding it until you can breach the walls and can storm it with much less casualties. However, it takes a lot of time, weeks or maybe months, meanwhile you have to delay your main objective. The enemy has time to organize. If winter comes, you probably have to retreat home, and instead of capturing a rich city, you only got an insignificant little fortress.

  3. You ignore it and go around. In this case, they will raid your supply caravans. Your large army needs a lot of food, gunpowder, etc, and leaving a fortress behind will make it harder for you to resupply. You will either lose supplies to them, or you need to guard your supplies which takes manpower out of your main army. Long campaigns were almost always decided on supplies.

Wars were long back then. Tens of years. In many cases a large army set off to invade, managed to get some foothold, but because of the above 3 factors they could only advance very slowly. Winter came, and they had to return home. Repeat it next year, possibly for the other side.

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.