How can the earth hill on a motte 'n bailey support stone?
It makes no sense to me, surely the weight of a stone castle would be way to much for an artificial earth mound to support? Why don't these castles displace the earth and sink into the mound over the centuries?
Re: How can the earth hill on a motte 'n bailey support ston
Martin Kallander wrote:
It makes no sense to me, surely the weight of a stone castle would be way to much for an artificial earth mound to support? Why don't these castles displace the earth and sink into the mound over the centuries?


One basic answer is you allow your motte to consolidate over a number of years to provide a firmer foundation. The second is that, in English castles at least, shell keeps were made. These are essentially a wall round the motte part the way up and tend to be thinner than the walls of, say, a square keep. This lightens the load and spreads it over a greater perimeter.
So the solution was basically just to build something small that wasn't too heavy? Were there any other methods to allow greater structures to be created on the mound, like for example, the mound being surrounded by a thinn wall so as to not give the earth anywhere to go?
After a few decades, the mound is no longer "artificial". It has been weathered and compacted enough to be indistinguishable from natural hills. Castles on these hills do not sink for the same reason that castles built on natural hills do not sink.
Well that is news to me, I thought castles on normal hills did sink if the hill didn't have a stone core. Aren't you ideally supposed to dig until you reach bedrock before building something like a castle?
Martin Kallander wrote:
Well that is news to me, I thought castles on normal hills did sink if the hill didn't have a stone core. Aren't you ideally supposed to dig until you reach bedrock before building something like a castle?

Ideally, yes.
Just speculation on my part that if the mound wasn't too high, had already been used for decades or more with only a wooden Keep and stockade wall near the top, when later the castle was upgraded to being made of stone, one might dig a foundation reaching the original ground level or even deeper ?

One reason might be to include a well at the bottom to reach ground water ? ( Probably a good idea in any case to dig a well first before creating the hill mound around it: Easier to do that than digging the well after creating the mound ? )

Alternatively in my imagination the original making of the mound could have been done around a hollow wood lined core with the intention of the core being at a later time being relined in stone and form the foundations of the Keep to be built a generation or two later ? The initial hole to reach ground water with a well ?

The walls surrounding the Keep at the top of the mound would not really need a foundation reaching the original ground pre-mound level ?

On the other hand the simplest answer is that the mound between the time of the initial wooden fortification and the replacing with stone would have settled and become as solid as a natural hill ? ( As mentioned in earlier posts. )

Oh, building the mound could be done like for some Celtic forts where wooden frames would be filled with soil, maybe clay and rock, built up in concentric smaller and smaller diameter layers, the outside of the mound covered with clay or earth where grass would grow hiding the inner framework.

By the time the inner wooden interlocking beams rotted the whole mound of earth, clay, small and large field stones would have become firm and solid ?

OK, a long purely " Theoretical Post " not supported by evidence just for the fun of it. ;) :lol: Just how I would do it if I was a Motte & Bailey engineer in period.
Here is an example of a cross section of a keep on a motte to help visualisation. It is Clifford's Tower in York

[ Linked Image ]

Note in this case the layers of the motte, where the foundations go, the well and the work the Victorians had to do to stop it falling down (The concrete reinforcement A and the enclosing walls are Victorian repairs).
There's no real nead to speculate, since there are literally hundreds of examples in the UK alone. I was even on an archeological dig at one back in 1983, Hen Domen at Montgomery, Wales. It's a cute little place, though now like many others, nothing remains of the wood and clay buildings, just the earthworks.

It's been too long since I read up on things like this, but I expect they never tried to build with stone on a fresh motte. Many many castles were built with timber and clay walls and buildings, though many were certainly rebuilt in stone in later generations. As others have said, that's the main issue--you have to wait until the motte is settled and solid to put anything stone on it.

There were also a few keeps that were built on flat ground, and the motte piled up around the outside. So you'd get the same visual (and defensive) effect. In at least one castle that I've been to, that mound was later removed and a door installed at the new/lower/original ground level. The changes are visible in the stonework.

You can certainly build a stone castle that is not on bedrock, it's just a matter of making proper solid foundations. But of course castles *tended* to be built on high spots, which are usually going to be rock outcrops.

But I *don't* think you want to try building up generations of "rotting timbers" and expecting that to be structurally sound. Medieval engineers had plenty of practice and some spectacular "fails" to learn from, and pretty much knew what they were doing.

Matthew
Matthew Amt wrote:
There were also a few keeps that were built on flat ground, and the motte piled up around the outside. So you'd get the same visual (and defensive) effect.

What are the benefits of doing this? To me it just sounds like you decrease the required length of ladders to scale the walls?
Martin Kallander wrote:
Matthew Amt wrote:
There were also a few keeps that were built on flat ground, and the motte piled up around the outside. So you'd get the same visual (and defensive) effect.

What are the benefits of doing this? To me it just sounds like you decrease the required length of ladders to scale the walls?


The mound would slope steeply down from the wall--there would be no place to rest a ladder. In fact it means you can't just put a ladder up to a window. As for other advantages, dunno!

Matthew
Matthew Amt wrote:
The mound would slope steeply down from the wall--there would be no place to rest a ladder. In fact it means you can't just put a ladder up to a window. As for other advantages, dunno!

Matthew

Eh, so long as you sharpen one side of the ladder you should be able to stab it into the mound for support, so long as the slope isn't like 60°+

[ Linked Image ]
https://i.imgur.com/JB5BoTz.png
Martin Kallander wrote:
Matthew Amt wrote:
The mound would slope steeply down from the wall--there would be no place to rest a ladder. In fact it means you can't just put a ladder up to a window. As for other advantages, dunno!

Matthew

Eh, so long as you sharpen one side of the ladder you should be able to stab it into the mound for support, so long as the slope isn't like 60°+


Okay with me, give it a try! While folks on top are raining death on your head... ;)

Matthew
Matthew Amt wrote:
Okay with me, give it a try! While folks on top are raining death on your head... ;)

Matthew

You say that as if scaling the walls with ladders isn't a very dangerous thing to do even in ideal circumstances :confused:

Though if the mound is comparable in size to the one Anthony showed earlier, then I can't see how you'd be able to assault it with a siege tower. Perhaps the mound forced attackers to use ladders instead of greater siege engines, and on top of that, made them less stable?
Quote:
Though if the mound is comparable in size to the one Anthony showed earlier, then I can't see how you'd be able to assault it with a siege tower.


You won't get near it with a siege tower, as it has a large ditch round the outside from which the muck to make it has been dug.
Martin Kallander wrote:
Matthew Amt wrote:
Okay with me, give it a try! While folks on top are raining death on your head... ;)

Matthew

You say that as if scaling the walls with ladders isn't a very dangerous thing to do even in ideal circumstances :confused:


Well, yeah, that minor detail, ha! All seriousness aside, look at that slope--how do you get your ladder to the top of it in the first place? Trying to claw your way up, holding your shield over your head with one hand while lugging your share of the ladder with the other, just not practical. Presumably you'd need ladders to get to the top of the mound in order to set the next set of ladders.

Quote:
Though if the mound is comparable in size to the one Anthony showed earlier, then I can't see how you'd be able to assault it with a siege tower. Perhaps the mound forced attackers to use ladders instead of greater siege engines, and on top of that, made them less stable?


Probably all of these issues can be solved, given time and muscle and casualties. Siege towers were very rare, too much tricky engineering and too easy for something to go wrong. Easiest solution all around was just to blockade the place and wait.

Matthew
Matthew Amt wrote:
how do you get your ladder to the top of it in the first place? Trying to claw your way up, holding your shield over your head with one hand while lugging your share of the ladder with the other, just not practical. Presumably you'd need ladders to get to the top of the mound in order to set the next set of ladders.

Maybe, but that's not the end of the world all things considered. You can still do it even if it is quite the hassle and you have to place down one ladder before proceeding with the one that will scale the wall. What I guess I'm trying to say is that you can still attack one of these keeps even if you haven't cleared the ground for assault before, which is one of the things ladders really are for according to the Heron of byzantium. To me these devices appear more so to be made to stop greater engines that besiegers often make use of to undermine defences less costly than scaling the walls with ladders.

Perhaps it doesn't reduce the required length of the ladders needed though... Two ladders with different angles are of course longer than how long a single ladder from ground to wall would need to be and without the mound you could get an even better angle which would further reduce the required length.

Quote:
Probably all of these issues can be solved, given time and muscle and casualties. Siege towers were very rare, too much tricky engineering and too easy for something to go wrong. Easiest solution all around was just to blockade the place and wait

I might be biased in this since I've mostly read about eastern stuff, but I get the impression that while the large siege towers like the one Robert built at Dyrrachium were quite rare, smaller ones were very commonly used. Since I don't think these ditches and mounds actually stop ladders, I don't think they would have made them so often if towers, rams, drills and all the other larger devices used by besiegers weren't common.

Anthony Clipsom wrote:
You won't get near it with a siege tower, as it has a large ditch round the outside from which the muck to make it has been dug.

Yea, although even if the ditch wasn't there, the mound would still accomplish the task. In any case:
[ Linked Image ]
Oh, the way a motte might be created can depend a lot on what the builders start with.

A) Flat ground build up from dirts, stone, clay, and a mix of whatever materials where available.

B) The suggested solution of building a very high stone tower and creating the slopped motte around it so that the foundations are on the original hard ground and/or down into solid rock.

Quote:
Matthew Amt wrote:
There were also a few keeps that were built on flat ground, and the motte piled up around the outside. So you'd get the same visual (and defensive) effect.


C) Tower built on an existing hill or rock outcropping that would be cut around the solid base of the tower to create a steeper and more regular slope.

As a general comment having a well in the basement of the Tower is much better than relying on rain and a cistern for a water supply ..... The best Castle in the World is pretty useless if there is no safe internal source of water.

A cistern can work if it rains often enough, but if there is a drouth during a siege a cistern might run out of water

https://history.howstuffworks.com/historical-figures/castle4.htm

From the above link:
Quote:
Wells and cisterns were collected water for the castle. Often, the ability to access freshwater was a key factor in whether a castle could withstand a siege. Wells could be located within the keep or in the bailey. Cisterns collected rainwater from the roofs. Some castles had rudimentary plumbing that channeled water from cisterns to sinks.
Martin Kallander wrote:
Matthew Amt wrote:
There were also a few keeps that were built on flat ground, and the motte piled up around the outside. So you'd get the same visual (and defensive) effect.

What are the benefits of doing this? To me it just sounds like you decrease the required length of ladders to scale the walls?


Benefit is the same as with glacis on e.g. Krak des Chevaliers.
1) You prevent enemy from gaining foothold near the wall itself. This is relevant in Middle Ages when siege towers were used to actually access the walls - extensions near bottom of the wall meant that tower couldn't be pushed up to the wall itself.
2) You prevent damage to lower sections of the wall. If you are not sure original curtain wall can hold up to bombardment, reinforcing the bottom of the wall is helpful because a) it improves stability of the entire wall and b) even if top of the wall falls, you still have some wall left.

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