All language subtitles for PBS.NOVA.Secrets.Of.Lost.Empires.S01E06.Medieval.Siege.DivX6

Secrets Of Lost Empire - 1x06

Knights in shining armor

charging each other
in great pitched battles -

that is the popular view
of warfare in the Middle Ages.

In reality,

most medieval conflicts
involved the attacking of castles,

and mounted knights were not
much use against stone walls.

A siege against a castle
could take weeks,

even months -

the attacking army

pitted against
a well-defended garrison within.

By the end of the 13th century,

the science of defensive
architecture had reached a peak.

Stone walls were built
thicker and taller than ever before.

And archers could easily
pick off advancing attackers.

To further frustrate attempts
at breaching the walls,

castles were situated
on rocky crags,

or surrounded by water.

But every advance
in castle defense

drove attackers to devise
better siege weapons.

During the Middle Ages
castles kept improving.

They kept improving
as weapons of attack got better.

And tactics was
this eternal balance

between attack

and defense.

200 years before cannon
appeared in Europe,

chroniclers make reference

to what appears to be the ultimate
13th century siege weapon -

an ingenious new form
of heavy artillery

that flung huge stone balls

with such destructive power

that castle walls were reduced to rubble.

But no ancient weapon
of this type has survived.

Were such claims gross exaggerations,

or did such a weapon really exist?

To answer these questions,

NOVA brings together a team
of experts in medieval warfare

who believe they know the secret.

It's chaos.

It's Wednesday, I think.

I don't have a clue
whether or not we'll finish.

Their task -

to build siege machines

capable of destroying a castle wall
at a range of about 200 yards.

I think that the thing'll
smash it up nicely, yes.

With just two weeks
to meet the challenge,

a siege mentality quickly sets in.

No modern builders have
ever managed to do this before.

And the whole thing could
twist and kick quite alarmingly.

This interplay between defenders and siegers,

it's still up in the air.

We could still take it,
then again, we could fail.

It's sort of
in the lap of the gods.

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Northwestern Mutual Life.

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from viewers like you.

Thank you.

In the year 1304,

Edward Longshanks,

more formally known
as King Edward I of England,

mounted the greatest siege
of his reign

against the Scots
and their castle at Stirling.

The attack dragged on.

Impatient for victory,

Edward ordered 50 carpenters to immediately
begin building a monstrous new weapon -

so powerful

it would breach the strong walls
of Stirling Castle.

Details about the weapon design
are tantalizingly vague,

except that it was nicknamed Warwolf,

and its appearance outside the walls

terrified the garrison.

Was it the atomic bomb
of the Middle Ages?

With one blow,

Warwolf leveled a section of wall,

successfully concluding
the siege of Stirling Castle.

What kind of a weapon was Warwolf?

What are we doing?

Are you ...

Do you want to go up there now?

Do you think you'd better
take a pair plyers up in case that ...

Hew Kennedy is a Shropshire
landowner and medieval armor expert.

10 years ago,

he became intrigued by a picture
of a machine drawn by Leonardo da Vinci.

It appeared to be a device
for throwing dead horses,

called a trebuchet.

Inspired by the power of a machine

that could hurl such heavy missiles,

Hew decided to try building one himself -

a quest which eventually led

to this piano-flinging contraption,

a mechanized catapult
made from a laminated beam,

scrap metal,

telephone poles

and steel cable.

In essence,

a trebuchet is a giant seesaw

with a very heavy weight
at one end

and a much lighter missile
attached to the other.

As the heavier weight drops,

the lighter projectile is whipped
by its sling towards the enemy.

Hew is convinced

that Warwolf, Edward's
great wall busting siege engine,

must have been a trebuchet.

If you chuck a thing that heavy
at a stone wall it'll shatter it.

Stone missiles are
a lot more effective than grand pianos.

To test out Hew's confidence in the destructive
capability of a medieval trebuchet,

NOVA is preparing
some hard sandstone balls

weighing 250 pounds -

and a wall.

It's made of sandstone

and lime mortar.

In construction and design,

it is based on the upper section
of a typical castle wall of the 13th century.

Hew wants to build a trebuchet

capable of knocking it down,

but at a range of 200 yards,

it will require precision

as well as brute force.

... from this point of view,

it's much more ...

Michael Prestwich, a medieval historian,

will ensure that Hew's next trebuchet

will be based
on an authentic 13th century design.

And I suppose when its got
to the top of its trajectory,

it starts coming down again.
(Yeah.)

It really looks quite frightening.

Yeah.

But I'm glad I wasn't standing underneath it.

It would bust up a building
all right, wouldn't it?

It's the first time I've seen
a full-scale trebuchet in operation.

To see the high trajectory of it

and the way the missile

and the sheer speed
with which it falls,

it is a fantastic sight.

Trebuchets began

in the Far East, in China.

But what they were there

were hand-pulled machines

worked by quite
large teams of men.

Prepare to loose, loose.

In many ways, quite limited
in what they could do.

The big advance came

when Arab engineers
got hold of these devices

and put a big counterweight on

so that instead
of teams of men pulling it,

the beam was pulled down
by a great counterweight.

They were far more potent
and far more effective.

These machines were ...

picked up by western engineers,

and by the middle of the 13th century,

it's very clear that

French, English engineers
were capable of building

really quite large machines.

Some of the best military engineers
were employed by Edward I -

a master of military tactics.

He was one of the most vicious
and single-minded rulers of his time.

Soon after ascending
the throne in 1274,

Edward decided
to squash Welsh independence

and bring Wales under his personal rule.

He was a bully, frankly,

and I think many people would think
of him as a really nasty piece of work.

He was utterly determined.

Nothing was going to get in his way.

Edward's strategy was to ring
the mountain stronghold of the Welsh prince

with a chain of powerful castles.

Richard Holmes is an historian
of military tactics.

He built eight new big castles,
which were really state of the art.

They were immensely strong,
well thought out.

And most of them could be
supplied by water

so they were very difficult
for the Welsh to besiege.

And Edward believed
that you controlled the countryside

by castles like this.

They're like nails

holding the landscape down.

And their garrisons
could issue out,

attack enemies in the area.

And until the castle was taken,

nobody could really
dominate that landscape.

They were extraordinarily
expensive to build,

and were a very severe drain
on the royal exchequer.

In the short term, though,

they worked.

Edward and other English lords

designed their Welsh strongholds

with the trebuchet in mind.

For example,

Caerphilly Castle was surrounded
by manmade lakes

which kept a besieging army
and their siege weapons at a distance.

Castles were what modern tactitioners
would call force multipliers.

They enabled
a relatively small garrison

to operate at the absolute
maximum of effectiveness.

And a castle like this
is carefully

organized to maximize defensive firepower.

There are loopholes in the walls
and the towers for archers to shoot through.

And here the walls
are cunningly organized

so that the second set of walls

is higher than the first.

And therefore an attacker
facing this face of the castle

not only gets the defensive
fire of the first wall,

but he's got archers
shooting at him

from the higher walls behind it.

It's a real nightmare.

At the end of the 13th century,

what was the effective range
of an archer?

And what was the effective
range of a trebuchet?

The historical reports differ.

Hew, how close are you going
to have to bring your trebuchet to the walls

to do serious damage, do you think?

Probably 200 yards,

we will need to be within
that to smash it up.

At 200 yards,

is Hew's trebuchet out of range
of archers defending the castle?

To find out,

a dummy representing the trebuchet's chief
operator is placed at that distance.

I'm sure an arrow would land amongst
us if we're at that range.

You could easily shoot 200 yards
with that massive bow of yours, couldn't you?

Yeah,

300 yards.

Yes.

Well at 200 yards,

I think it would be ...

putting you a bit worried,
wouldn't it?

Yes, it would.

I'm the first to accept
that from this sort of range

the trebuchet would be doing
serious damage to the castle walls.

But I think
this does suggest that ...

it's no easy business.

And the garrison
that knows its business

can probably

keep a trebuchet
at the very limit of its range.

And the fact that we had
some going over the top

I think is mighty hopeful
from the archer's point of view.

I wonder what happens if you ...

slap one into him from here?

Could I... Come on then.

It's all right,
he's swallowed it, hasn't he?

Gone ... gone right through ...

right through the dummy,

kept only in by the fletchings.

Bit of a bellyacher I reckon, yeah.

Edward's castle-building
campaign in Wales

had taught him how to design
well defended fortresses.

Turning his attention
to conquering Scotland,

did Edward also have the ability
to successfully attack them?

As the king marched northwards
to take the castles that guarded Scotland,

he brought with him some
of the biggest siege engines,

or trebuchets, ever built.

The siege of Caerlaverock,

conducted by Edward I in 1300,

we've got remarkably a really good
account of this in a contemporary poem.

It describes the way in which
the knights rode up to the castle

all in their great armor,

trying to perform great deeds of valor.

In fact, they were driven back
by the garrison,

hurling stones and such at them.

And it wasn't the knights,

it wasn't these people
with the great acts of bravery.

It was the engineers,

men of really quite low
social status in comparison,

with the great siege engines.

It was they

who compelled the garrisons
to surrender.

And the poem describes the way

in which the great boulders came down
from the sky, into the courtyard,

crashing down,

causing all sorts of damage
and mayhem inside.

The minute the casualties started,

the garrison simply surrendered.

So it wasn't the knights,

it wasn't a great act
of chivalry to capture this castle.

It was the work of the experts,
the engineers.

It's difficult to tell, I mean ...

that one's obviously got a ...

Joining Hew Kennedy
in his quest to build a trebuchet

is mechanical engineer Wayne Neel,

a professor from Virginia Military Institute.

... is the golden section.

This one actually is one to two,
and this is one to three.

Wayne will design the trebuchet.

He is basing it on a picture he found
in a 13th century Spanish manuscript.

The illustration gives no idea
of the true scale of the trebuchet

because the artist
has made the machine smaller

than the soldiers standing next to it.

If the drawing isn't practical
from all points of view,

you begin to wonder about
all the other points of view.

It may be that the things they have got
in the right proportion they did by accident.

Even an artist like Leonardo will draw
a plan for something that is totally impractical,

but it indicates how it could be made.

That's all.

It indicates how it could be made.

With the manuscript as a starting point,

Wayne uses a combination
of engineering theory

and trial and error

to come up with a working model.

The prototype looks
promising to Marcus Brandt,

a carpenter who will
help Wayne build the trebuchet.

But there's a problem.

The model rocks dangerously.

This would be a serious flaw

in a full-size trebuchet
with several tons in motion.

The machine basically tends to wanna ...

tip forward as that weight comes down.

It wants to drop straight down,

so it tends to pull the machine
forward making it in this case tip.

To resolve the problem,

Wayne re-examines the medieval
illustrations of this type of trebuchet.

He's struck by the fact

that many have wheels,

so he decides to build a new model.

Not only do wheels eliminate
the tendency for it to tip over,

the movement also boosts
the trebuchet's performance.

Shoot away, come on.

Hew doubts that wheels will make
a trebuchet throw farther,

so he insists on a demonstration.

For the first throw,

Hew holds down the model.

The projectile travels 20 feet.

Now let's try it with -
letting it loose.

Yeah. Well, it's certainly better, isn't it?

Yes. I didn't ...

When the trebuchet is allowed to roll,

the missile goes an extra 10 feet.

Why?

The falling counterweight
drives the trebuchet forward.

Like a pitcher stepping forward,

this adds momentum to the throw.

The forward motion also
permits the counterweight

to drop further in a straighter line.

The closer the counterweight
follows this optimal path,

the more energy it captures for throwing.

What I find odd is the idea about
it moving and having to move

in order to give more
energy to the missile.

I would have thought this was -

on the face of it, nonsense.

But obviously if Wayne's tried it,

and it goes further,
then it can't be argued with.

Now that Wayne has confidence
in his model,

the project moves to Loch Ness
in the Scottish Highlands

for a full-scale test.

The trials will take place
in the shadow of Castle Urquhart,

which may have been besieged
with similar weapons

during Edward I's
Scottish campaigns 700 years ago.

Wayne and Hew arrive
at Castle Urquhart

to inspect the timber
that is delivered by barge.

As in the Middle Ages,

heavy duty English oak

is the choice for building
the carriage and trestles.

But the throwing arm will be
made from a more lightweight wood,

Douglas fir.

Wayne calculates

that a tree trunk of at least
two feet in diameter is needed

to withstand the stresses
of hurling 250 pound balls.

How about this one, Wayne?

It's the right size.

That would be the right diameter.

Be a shame to cut that down, wouldn't it?

Yes.

Let's get the chain saw and whack it down.

Would we have a go?

Get out of it!

Haul away.

After it is floated across Loch Ness,

the log is quickly hauled ashore.

Work immediately begins

on hewing it
into an eight-sided throwing arm.

The next job is to assemble the base.

40 carpenters,

mainly from the United States,

but also from Britain and Germany,

have volunteered
to spend their vacation here.

They're all timber framers

who specialize in traditional
construction techniques.

Without nails,

they connect large pieces of wood

using mortise and tenon joints.

Beautiful.

1, 2, 3 ...

While the timber framers immerse
themselves in medieval methods,

Wayne employs the tools
of a modern engineer

to check and recheck his design.

In particular,

he's hoping that the wheels will give
him the same boost in performance

as they did on the model.

Spin on, spin on.

Up at the target wall,

work is almost complete.

The wooden structures on top

are called hoardings.

They provided additional
protection for defenders

during the siege.

Attackers would build
similar barriers

to protect the trebuchet team

from arrow fire.

Well, this is the target wall

that we've got for the trebuchets -

a modern reproduction of a castle wall.

It's a pretty good reproduction I think,

it's got all the details of the crenelations.

And what's important about it

is the width.

It's a good five foot thick.

The way that it's formed

is that there's an outer skin
on either side,

and within that
a fill of rubble and mortar.

And that provides a very solid core.

This is exactly how
they did it in the Middle Ages.

And ...

I'm very glad
that I'm not standing here

while the trebuchets are actually shooting.

The target wall is modeled
on the outer walls of Harlech and Caerphilly,

two of the best
defended castles in Wales.

Faced with the daunting task
of taking a castle like Caerphilly,

what siege tactics
would an attacker adopt?

A castle like Caerphilly,

like this one,

presented an attacker
with a knotty problem

because it's got layers
of defenses,

with sandwiches of water between them.

A bit like the layers of an onion.

So an attacker arriving here

would encounter the moat,

a water defense,

so that he couldn't mine underneath it
without his trenches being flooded.

His best bet if he possibly can

is to take the place
by surprise or by guile.

To trick his way in -

to get in before
the garrison's ready for him.

If he can't do that,

he's then got
to mount a formal siege.

And ultimately ...

he'll starve it out.

Gates had once been
the castle's weakest point.

But by this stage in history,

they'd become its strongest.

They're defended by gatehouses,

these are very powerful towers

with arrow slits in them.

So anyone attacking the gate
is subjected to close-range fire.

And there's a portcullis

which drops down just behind the attackers,

and even if an attacker
does manage to take the gatehouse,

then he's got another moat,

two more gatehouses,

and he's got to do
the whole rotten business

all over again.

Meanwhile, rotten weather
has besieged Castle Urquhart.

And after a week
of daily downpours,

the trestles that support
the throwing arm

are ready to be raised.

Pull.

Pull.

Pull.

At the top of the trestle,

the throwing arm rotates
on an axle

that has to be both strong

and exact.

... and counterweights
so it has to be fairly precise ...

Marcus Brandt has taken on the job.

Well, we've got
to address the issues of axles.

We've got two sets
of axles with this fixed arm,

fixed counterweight machine.

We've got the axles down here
to carry the wheels,

and we've got this more
precise axle up here

which carries
this 8 tons of weight and ...

arm.

And it has to be fairly precise.

We've set up a great wheel lathe

which is a precursor to modern lathes.

It's just a great big flywheel.

It's powered by muscle

and it turns this 10" x 10"

down to an 8" x 8".

Marcus restores old buildings
in Pennsylvania,

and has enthusiastically embraced
the idea of using medieval technology.

It's a very medieval feel
to the whole project.

We've got all the trades going at once.

We have the stone masons busy,

we've got all the carpenters
and the axes flying

and the chips and the smoke and the mud.

Boy, if ...

if it weren't for the jets
flying overhead occasionally,

you'd think you're in the 12th century.

Villages were often established

next to the castle
of a nobleman or the king.

English society was very hierarchical,

with the king and his nobles at the top,

and then the rest of society
cascading down from that.

Now the castle wasn't
just important militarily,

they were an economic power as well.

There were communities
built up round the castle

to supply it.

And the castle provided protection as well.

At their best

these noblemen were protectors,

at their worst they were ...

often something rather like mafiosi, uhm...

leeching off the local countryside.

So living under the shadow
of a place like this

had advantages,

but disadvantages too.

How you doin', Phil?

Goin' up too much there?

In order to position
the heavy throwing arm,

the timberframers place an A-frame

above the trestles
to support the pulley system -

a standard medieval device.

A block and tackle

dramatically reduces the number
of people required to pull on the ropes.

Now block and tackle is
a fairly simple device.

It magnifies your pull.

If I were to lift my own
body weight with a single rope,

I would have to pull
down 200 pounds

to lift my 200 pounds of body weight up.

With this,

I'm hooked up
to this double sheath pulley,

and I've got four lines
which share the load equally,

so 200 pounds here

is only 50 pounds
on each one of these ropes.

So to lift my 200 pounds up,

I only have to pull 50 pounds here.

Now mind you, I have to pull
four times as much rope,

but it really works.

The next phase of construction

is the most dangerous.

Without the help of a modern crane,

the timber framers must trust
the strength of two slender poles

and the rigging of their ropes

in order to raise
the one ton throwing arm.

One accident,

one slip,

one failure hidden
in the heart of this timber

and we're out of business -

simple as that.

It's looking real good right now,

going right on in there
like we planned it seems.

We are in place.
Yeah!

With the throwing arm in position,

Wayne needs to attach weights
that will power the machine.

He chooses lead

because he believes lead was used
for the counterweight of Warwolf,

the mysterious and terrifying
siege engine

that clinched the assault
on Stirling Castle.

There is good historical
evidence for this.

In a letter Edward wrote
just before the siege,

he demanded that lead
be removed from all the churches.

One of the things that they needed
for the siege of Stirling

was heavy weights
for the counterweights on the engines.

And they sent orders out

to strip all of the church roofs
in the entire surrounding area.

So all of this lead, lead sheets,
would have been brought to the siege

and then melted down
in order to form the counterweights.

Wayne's calculations tell him

that in order for his machine
to throw a 250 pound ball,

he'll need about
six and a half tons of lead counterweight.

It takes a week
to melt down the scrap

and form it into a collar
that can be bolted onto the arm.

Wayne's come up with
a really neat solution

for a lead counterweight
made various pieces

bolted together.

But it is expensive.

Lead is difficult
to get hold of.

It's complex to make this.

There is a much easier solution,

which is to use
a large box as a counterweight.

Something like this,

which you could fill with earth,
with stones, with anything you'd got.

Fill it up.

You could put as much or
as little in as you wanted,

and that would affect
the range of the machine.

And you'd simply then have to put this ...

box on the machine,

swiveling ...

roughly like that.

A survey of medieval
illustrations suggests

that swinging counterweights
were the more popular design.

A man who has been working
with them longer than anyone else

is traditional French
carpenter Renaud Beffeyte.

Renaud is convinced that Edward's
great siege engine, Warwolf,

had a swinging counterweight box.

The simple design of the box
makes it not only cheaper,

but easier to build than one
with a lead counterweight.

Here we got.

And Renaud has found
graphic accounts

of the destructive power
of some really big siege machines.

I found account medieval -

An account,
-Yes.

a medieval account.

And they pay 300 bullets
in three days,

then they shoot 300 bullets
on the same place on the same wall.

After three days,
the wall was destroyed.

So you think the real
purpose of something like this

is ...

is simply to ...

attack a castle from a distance

and bring the wall down?

Yes.
Yeah, yeah.

500 years before Newton's apple,

medieval engineers had figured
that trebuchets with a swinging counterweight

are the most efficient
at using the force of gravity.

Like adding wheels
to a fixed-counterweight trebuchet,

the hinge allows
the swinging counterweight

to descend further
in a straighter line,

capturing more energy for the throw.

15 years ago,

Renaud came across the notebook
of the 13th century French architect,

Villard de Honnecourt.

In it he found the plan
for the base of a trebuchet

and a description
of the swinging counterweight box.

Unfortunately,

the page showing the rest
of the trebuchet was missing.

But with his knowledge
of medieval carpentry

and his experience
of building over 30 small trebuchets,

Renaud realized that
if the design were ever built,

it would be monstrous -

the height of a five-story building.

Ever since this discovery,

Renaud has wanted
to construct the full-size trebuchet.

Finally, he will get the chance
at Castle Urquhart in Scotland.

At the start of a medieval siege,

a trebuchet engineer
would typically seek out

as big a throwing arm as possible.

Renaud inspects a good-sized oak log
that he hopes will be suitable.

Using the same geometric principles

employed by the medieval engineers
who built castles, cathedrals and siege machines,

Renaud starts designing his trebuchet.

The key decision is
where on the throwing arm

to position the main
pivot point, or fulcrum.

Medieval engineers
worked this out by observation.

In this largely illiterate society,

carpenters used animal
figures like these

as an aid to remember
geometric formulas.

Now that Renaud knows
where to put the main axle,

he can design the trestle,

base

and capstans

to raise the counterweight box -

because they are all sized
in proportion to the throwing arm.

But just as he begins
building the trebuchet,

Renaud is called back to France.

In his absence,
work progresses on the base.

Work also begins

on drilling out the main
axle hole in the throwing arm.

Unfortunately,

there is some confusion
about the size of the opening,

and a nasty surprise
awaits Renaud's return.

Hi.

Good morning.
Hi. Good morning.

Renaud's been away
for a couple of days,

and while he was away,
we cut the axle hole.

It's quite apparent that a lot of meat
has gone from the timber

and we're left with quite
thin sections on either side.

I think the beam,

the throwing arm, can break here,

in this part.

Renaud's concern
is that we've gone

too much to this extreme where we've taken out
too much wood of the throwing arm

and made the axle too strong,

and his concern of course is
that on our first throw,

that it's going
to do something like that.

Renaud is left with no alternative

but to hope that a couple
of planks will be strong enough

to splint the weakened throwing arm.

Finally,

work starts on raising the great trestles.

With each passing day,

the situation at Castle Urquhart
more and more resembles a siege of old.

With two trebuchets to finish,

there is a nagging feeling
that Renaud's machine may not get done

before the timberframers must return home.

Over at Wayne's trebuchet,

work on attaching the lead
weights is finally finished.

All that remains

is to cock the arm.

Even with the help of pulleys,

this requires 40 people.

With a 13,000 pound counterweight,

it's a much bigger job
than any one imagined.

And it will have
to be repeated for each fling.

The trigger mechanism
is not strong enough,

and buckles alarmingly

as it takes the full weight
of the throwing arm.

It's bending as we're
releasing the arm,

and we're wondering whether
it can hold the weight right now.

To avoid an accidental firing,

they reinforce it with a length of chain.

They've got lots of engineers on this
and maybe they've got it right,

but I think it's quite
difficult to get it right.

It's chaos,

the sun is going down,

I don't have a clue whether
or not we'll finish

even one of these machines on time.

Well, we're under the gun now.

It's kind of touch and go whether
we're gonna get this thing put together

and actually fling both machines,

but if I know this crew,

come hell or high water,
we're gonna make this thing fling.

There goes your light (laughter).

The next morning
a 250 pound sandstone ball

is quickly positioned
in the sling for the first throw.

I'd rather have a blow this long...

It's got about a 50 percent
chance of going in the right direction.

It could go in the lake
there by mistake ...

because these adjustments are ...

not well known to us.

You ready?

This is it.

One,

two,

three,

fire in the hole!

Even with 12 timber framers pulling,

the firing pin won't budge.

It's quite normal that,
I mean, triggers are very stiff.

We found that at home.

It takes a lot of effort,

which is as well, in some ways.

Despite Hew's predictions that a trebuchet
on wheels would shake itself to pieces,

the reverse is true.

Wheels dampen the recoil.

Everything appears to be
working as Wayne predicted,

except the range.

The ball only traveled
about 170 yards,

falling short of the wall.

What are we ...

30 yards short,
and about 5 feet low.

I thought the throw was flat,
which means we've got to -

I think shorten the sling
so it releases sooner

and goes higher,
which should get us to the wall.

Just like his medieval counterpart,

Wayne uses a process
of trial and error

to alter the trebuchet's range

by adjusting the length of the sling.

With the first throw,

a long sling resulted
in a late release

and a low trajectory.

By shortening the sling,

Wayne believes the ball
will be released earlier,

resulting in a higher path.

Wayne's adjustments
have the desired effect.

The second throw has perfect range,

just missing the target
to the right by two feet.

I think we took the King's ear off.

Good job, Wayne!

So it needs a slight adjustment,

and then it would be a direct hit.

Tomorrow is another day.

What will be the last day
for Wayne and his team dawns,

with the wall still intact,

but clearly under threat.

Meanwhile Renaud's trebuchet
is still not finished.

This morning they rush
to complete the counterweight box

that is hinged to the throwing arm.

We've got the one treb built;

the other one is
about 99% of the way there.

We flung two stones
last night with Wayne's treb,

but we really don't want
to let Renaud down,

and we don't want
to let ourselves down.

We really want to see
this thing fly before we go.

Still,

with time so short,

it's unclear that Renaud
will get a chance

to fire his trebuchet at all.

After last night's narrow miss,

Wayne's trebuchet is repositioned
to be more in line with the target.

All we're doing is shifting
it slightly to the left.

We were throwing
to the right a little far.

So we've shifted it
about one inch,

so that hopefully
we'll be dead on center.

With the same
250 pound ball as yesterday,

and the sling at the same length,

Wayne believes
he is now dead on

to hit the wall with his third attempt.
(... three, two ...)

... one.

Fire in the hole!

The third shot is identical
to the second in distance.

At a range of 200 yards,

adjusting the wheels
one inch to the left

placed the missile bang
on top of the hoarding.

We've gotten wood,

I don't know if we've
contacted any stone yet.

But we've knocked the hoarding pretty well.

It was maybe a little high,

and we've come down a little bit.

That must be the old hole
there, mustn't it?

That's the hole.

It's still a bit
on this side, isn't it?

If you'd been standing
under that hoarding, you'd have had a jolt.

With the trebuchet lined up
on the target,

Wayne only has to shorten
the range by a hair

to hit the stone battlements below.

So this time what we've done is
lengthen the sling about six inches,

so we're hoping
to fire a little bit flatter

and get to the top of the hole -

the top of the wall.

It's quite difficult,

I think probably, isn't it,
on those small adjustments?

I mean, do you think -

Yes, small adjustments
are difficult to do.

We could ...

perhaps not get
so lucky this time,

but it's been very good so far,
hasn't it? (Well, we'll see.)

Worried that this may
be the last attempt,

Wayne makes a sudden change of plan.

He replaces the 250 pound ball
that he's been using

with a jumbo 300 pounder.

Wayne figures that the heavier ball,

clocked at a speed
of 127 miles an hour,

should breach the wall.

But he is wrong.

We're going back to the 250 pound ball,
instead of the 300

and see if we can get
a little bit more height.

They've only got time
for one more shot,

the American team, and ...

they've been very near,

but they might miss it again.

And if they don't get it,

do you think
you can get it with yours?

Maybe if we are more lucky,
then we can destroy this wall.

Yeah.

Well, we'll see.

It's French against Americans.

No, it's - no, no,

it's not against.

That's your way.

Putting on their kilts
for good luck,

Wayne's team rushes
to get in one final shot.

We did it!

Come and take a look
at the rocks over here.

It just pulverized the stone
on the inside.

It confirms what we came here
to prove, didn't it?

We - they've had a lovely hit,
smack in the middle,

and it smashed it.

And it's busted it
right through to the back.

So it's quite obvious that
if you've got one of these trebuchets

and you've got a castle like this,

and you've got plenty
of time to shoot it,

you're going to knock
it into a powder.

We can reduce this to rubble.

Intoxicated with success,
the timberframers bid adieu to the Highlands.

But the next morning,

Renaud is heartened to find
that he's not been completely abandoned.

Ed Levin

and a handful of the Americans
have decided to stay on in Scotland

to help finish the job.

I'm sure it's good enough.

No, it's linking to the second...
What's happened?

The biggest concern

is whether the throwing arm
has been fatally weakened

at the point where the main
axle passes through it.

To avoid stressing the arm,

Renaud decides to only
partially load his counterweight,

using four tons of sand
in the 12 ton capacity box.

But there are risks to this approach.

We're all suitably cautious

in having the 250 pound sandstone ball end up
in the castle wall rather than in the loch,

or drop down on the machine, or ...

any of the other places
it has historically been known to go.

Nobody knows quite
what they're doing,

so that's what makes it fun.

A moment of birth.

And terror.

Yeah.

Well, birth is usually
accompanied by terror.

Now we are ready for shoot.

It's ...

getting me nervous.

... three,

two,

one,

fire in the hole!

The heavy ball and relatively
light counterweight

result in the missile landing
dangerously close to the trebuchet.

Well yeah, I mean,

we knew that there wasn't enough
weight in really, didn't we?

It was just an experiment.

The counterweight is not so heavy.

We must put two bag more.

Two tons.

Of sand.

Yes, of sand, yes.

Two more tons of sand are added.

I don't think there's enough weight
for it to go really well yet.

This machine wants a lot of weight.

10, 12 tons probably,
to make it go properly.

Renaud thinks if we keep
putting little bits in,

he might just get there
without busting the axle,

which is natural, of course,
because it's his machine.

Fair enough.

Five!

We are going to get a good shot.
(Four!)

I'm sure, sure, sure.
(Three, two ...)

... one,

fire in the hole!

Renaud's optimism is justified.

The missile falls just
a few yards short of the wall

and a bit to the right.

The team decides
to give it one more day.

But the next morning
starts with snow,

followed by a heavy downpour.

Well, basically we're
at the last day, we've got -

between the rain and the mud,
we've got a rigger's nightmare.

It's really taken
its toll on the ropes,

the mud grinds in
and it starts tearing up the fibers.

The water helps make the rope stretch,

and if you look around the place,

there's ropes in the mud
and no rigger likes seeing that.

So we're doing the best we can
to keep our ropes clean,

but it's an uphill battle.

Last night's final shot
was short of the wall

because it was thrown too high.

Renaud believes

the sling is slipping off
its prong too soon.

So to delay release
and lower the trajectory,

the prong is bent forward.

We've got the right amount of loft,

we've got the right amount of range,

we're just ...

missing the target off to the side.

For days, Renaud has suspected

that his trebuchet is pointing
just to the right of the wall.

But the loaded machine
is too heavy to shift,

and he faces the possibility

that he may have to go home

having achieved only a near miss.

At the last minute,

Marcus offers a solution.

If we had our preferences,

we'd be able to move
the machine over a little bit,

but we're afraid
of shattering the machine,

particularly with all
the weight in the basket.

So we're gonna move
the channel of the ball

a little bit to the side
so we can change our angle of attack.

The range is good,

but we just want shift it
over to the left a bit.

By shifting the channel that holds
the ball slightly to the left,

they hope to redirect the missile.

It works -

almost.

Another three feet and Renaud
would've had a direct hit.

Unless shifting the channel
was just a fluke,

one more nudge to the left

should bring the trebuchet
right on target.

Go, baby! Come on!

Oh, that looks good!

Perfect, yes. At right.

Yeah!

After two throws which are slightly
high of the wall itself,

Renaud orders a minute
adjustment of the prong

in order to lower the trajectory.

With frayed ropes and a storm
threatening to close down the siege,

everything now hangs on Renaud's
ability to quickly get on target -

and he does.

A bull's eye on the battlements.

Well done!

This whole wall,
if you run your eye down here,

it's bellied out,

there's cracks all through it.

Anybody standing back here
would've been mincemeat.

In a real siege

it would only be a matter of time

before the wall
is reduced to smithereens.

In terms of the kind of dialogue
that existed between attack and defense,

it is very clear now to me that the ...

appearance of the trebuchet on the scene
shifted that balance radically in favor of attack.

I've gained tremendous respect
for the medieval engineers.

They were able to build a ...

frightfully powerful

and highly accurate
and easily adjustable machine.

If you're under siege,

you've got to try to knock these things out
before they're actually built,

cause once they're built,
you're sunk.

The trebuchet is ...

this big machine
who can broke the wall

and also ...

a trebuchet must be the ...

Wolfwar.

Warwolf.

Wolfwar?

Warwolf.

Warwolf.

It's so difficult,

we must change this name.

Warwolf.

It is clear from the experiment

that both types of trebuchets work.

Because it could so easily
be increased in weight,

the swinging box design
was the improvement

that tipped the balance
in favor of attack.

So the great wall-busting siege engine
Edward employed at Stirling Castle

was almost certainly a trebuchet

with a giant swinging counterweight.

The weapon that dominated
siege warfare for 200 years.

It was not until
the late 15th century,

the end of the Middle Ages,

that the superiority
of cannon clearly emerged,

and the trebuchet ...

vanished into the mists of time.

Become a medieval engineer.

On NOVA's Website,

build your own trebuchet

and knock down the castle walls.

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