1. A motte and bailey Castle
Easy to build. (They could be built in less than a week) Easy to defend. (And remember, the Normans were an invading army) Could easily be modified later (e.g. A stone tower rather than wooden tower) Over 70 were built during William's reign as King of England

2. Main features: Defensive features:
The Motte is hard to attack, as its sides are quite steep.
On average a Motte was no higher than 5 metres.
There are some examples of Motte's that were much higher than this though, Clifford's Tower at York for example.
The ditches around both the Motte and the bailey would prove a difficult obstacle to overcome for any attackers, with the fence and possibly a drawbridge to overcome immediately after the ditch the castle becomes a very strong fortress.

3. Main features: Defensive frailties:
A Motte would be susceptible to collapse under the weight of a castle,
whilst they were good in the short term the castle would require shoring up and possibly even rebuilding in the longer term.
Wooden fortifications are also susceptible to simple methods of attack.
They burn for example and given time would rot due to inclement weather.
Later stone structures on these sites would of course overcome this problem (although the Motte itself would be placed under greater strain).

4. Capturing a castle!
Launceston Castle

5. Here are some notable sieges
Rochester Castle (1215)-the fall of this mighty fortification produced temporary loss of confidence in castles.
Dover Castle (1216)-mining of the castle was only thwarted by a relieving army. It produced the building of spur to stop the mining of castles. A spur is a wall or earthwork projecting sharply from main defences.
Berkhamsted Castle (1217)-Henry III ordered his constable of the castle to surrender on humanitarian grounds.
Bedford Castle (1224)-One of the best documented sieges. The garrison of the castle was hanged after defeat.
Kenilworth Castle (1266)-the castle held out for six months against Henry III, and only surrendered because of the lack of food and disease.

6. Attack the castle! Offence: 1. Direct Assault 2. Siege Tower
3. Trebuchet
4. Battering Ram
5. Tunnel
Defence:
6. Walls 7. Archers 8. Gatehouse 9. Moat

7. Medieval Arms Race
War in medieval times was about the control of land.
Garrisons of knights and other soldiers who lived in castles controlled the land around their stone fortresses.
To conquer a territory, an attacking army would have to strike and take these central strongholds.
To do so, they would launch a siege.
Over the centuries, medieval armies developed military strategies to fight a siege.
Weapons of war also evolved, often in response to the technological advances of the enemy.
By the mid-12th century, siege warfare had developed into a science, practiced by an engineer corps called ingeniatores.
Here we describe some of the major weapons and strategies used in what became a medieval arms race. Let the siege begin.

8. Direct Assault
A direct assault was the most dangerous way for attackers to try to take a castle.
Soldiers either scaled walls with ladders or overran castle walls breached by tunnels, battering rams, or artillery.
Sometimes they attacked two or three spots around the castle at once to surprise their foe or divide castle defences,
and sometimes they approached the wall hidden within a trench or tunnel.
Archers and crossbowmen would cover soldiers while they tried to break a wall or storm over it.

9. Direct Assault
Defenders, perched on the castle wall or in narrow windows called loopholes, literally had the upper hand.
Archers rained arrows down on attackers,
Soldiers
pushed ladders off the wall with forked poles,
dropped rocks or
fire pots filled with burning tar, or poured scalding water, wine, or hot sand (which could enter armour) down onto those below.
Attacking armies sometimes blockaded a castle instead
Though safer than fighting, starving occupants out of a castle was not always straightforward.
Attacking armies were reluctant to wait out a winter without permanent housing.
Castle dwellers kept stockpiles of food and drilled water wells within the castle's walls.

10. Siege Tower or Belfrie
Attackers sometimes built a siege tower to scale castle walls.
Soldiers lay in wait inside the structure as others wheeled it to the castle.
Once there, the soldiers lowered a drawbridge at the top of the tower onto the castle wall.
Some towers were almost 100 feet high, and in the siege of Kenilworth Castle, fully 200 archers and 11 catapults were crowded into a single tower.
Siege towers were difficult and time-consuming to build,
Castle defenders could burn them down with fire arrows or firepots
Sometimes castle knights launched surprise raids on a tower to destroy it during construction.
To protect their siege engine, attackers draped it with rawhides of mules or oxen.

11. Trebuchet
During peacetime, castle commanders used trebuchets to launch roses at ladies during tournaments.
But during a siege, these missile launchers were one of the most fearsome weapons of medieval times.
Early trebuchets were powered by muscle, but later versions relied on a huge counterweight that swung a long arm.
When the counterweight was dropped, the device launched a missile from a sling at the end of the arm.

12. Trebuchet
Caerlaverock Castle
Trebuchets could launch missiles hundreds of yards in large, lobbing arcs at or even over a castle wall.
The best trebuchets fired stone missiles weighing up to 400 pounds—big enough to do serious damage to a castle wall.
Attackers also used them to launch dung or dead animals into the castle with the intention of spreading disease.
Sometimes they shot out the severed heads of enemy soldiers
If a trebuchet was set up too close to a castle, archers would harass its builders with arrows shot from bows or bolts from crossbows.
Castle defenders would try to destroy rising trebuchets with catapults shot from the castle wall or with sneak attacks to burn it down.

13. Battering Ram
Siege armies used a battering ram to break down a gatehouse door or even smash a castle wall.
To shield themselves from attack, they built a covered shed, in which they hung a thick tree trunk on chains suspended from a beam above.
Carpenters tapered the trunk into a blunt point and capped it with iron.
The slow forward movement as the battering ram was wheeled toward the castle wall earned it the nickname "tortoise."
Soldiers swung the hanging trunk back and forth, and the forward end of the trunk moved in and out of the shed like a tortoise's head, battering its target.

14. Battering Ram
Castle defenders tried to burn the shed down with flaming arrows, though attackers responded by covering the shed with animal pelts or earth to make it fireproof.
Defenders sometimes dropped mattresses down to cushion the blows or lowered grappling irons to grasp the trunk, preventing it from swinging.

15. Tunnel
Men called sappers sometimes dug tunnels to gain entrance to a castle and thereby launch a sneak attack, but more often, these miners dug tunnels beneath a castle wall to destabilize and topple it.
They supported their tunnels with timbers, which they then burned to collapse the tunnel—and, hopefully, the wall above. A special member of the team was the torchman. He would set the tunnel on fire and run for the tunnel opening .
To defend themselves, castle dwellers put out a bowl of water and watched for ripples that might indicate digging.
Sometimes the castle's garrison built counter-tunnels; if the two tunnels met, fierce battles ensued underground.
Mining was undertaken at Rochester Castle in 1215, at Dover Castle in 1216, and at Dryslwyn castle in 1287.

16. The mangonel
The mangonel was introduced to the Normans by the Byzantines.
This siege engine was used for a century after the Norman Conquest in 1066, and it is also referred to as a Mangon.
It consisted of a heavy frame which supported a long arm with a cup or sling at the free end.
The other extremity passed through a ropes, called a skein, stretched between upright posts.

17. The mangonel
The ropes would be twisted by capstans, called capitals, and then the free end was pulled down by a winch or windlass.
When it was in a horizontal position the arm would locked into position and the cup or sling would be loaded with a stone or incendiary material.
The arm would be released and it flew up by the whip effect until it hit a horizontal padded stop between the upright arms of the frame.
The projectile would have a low inaccurate trajectory. The range would have been around 200 yards.

18. Archers
Both attacking and defending armies had archers, though those shooting arrows from the castle had a great advantage.
First, castle archers were almost always launching arrows from a higher position than castle attackers, which extended their range and provided them with a good view of their human targets.
The castle wall also protected them well.
Loopholes, the narrow slits that archers shot through, were often splayed to the inside, allowing castle archers a wide latitude of targets.
The design enabled archers to hide off to the side of the loopholes while reloading, giving them protection from the rare arrow that did find its way in.

19. Archers
Horizontally cut loopholes gave castle archers an even greater range.
The archer had two weapons to choose from.
The most powerful was the crossbow.
Barbs on the head of a bolt, the stout arrow shot from a crossbow, were often coated with beeswax to help them pierce armor.
Crossbows took longer to load than the simple bow or the longbow.
A longbow archer could shoot about 12 arrows in the time it took to launch a single bolt.
Moreover, the longbow could send arrows as far as 1,000 feet.
But longbows took tremendous strength to shoot and much practice to control.

20. Gatehouse
The gatehouse, the castle's entrance, was the early castle's most vulnerable point.
Later, military engineers bolstered it with impressive defenses.
A drawbridge could be pulled back, lifted, or pivoted like a see saw,
while portcullises—iron-covered wooden grills that moved up and down in front of the gatehouse door—provided additional protection.
Castle dwellers could also slide wooden beams behind the doors to reinforce them.
If attackers broke down the outer door and entered the gate's passageway, they ran the risk of being trapped.
Sometimes defenders would drop a portcullis behind them.

21. Gatehouse
Roofs above gate passages often had so-called "murder holes" through which castle soldiers could drop burning oil, hot sand (able to enter armor), or scalding water onto enemy soldiers.
Loopholes in the walls of the gate passage also gave defending archers—only feet away from trapped attackers—a deadly advantage.

22. Moat
Moats surrounding castles protected them from siege towers and battering rams, war machines that were only effective when wheeled to the wall.
It also made digging tunnels underneath the wall far more challenging.
To get across a moat, the attacking army sometimes filled the moat with rocks and soil or built portable wooden bridges.

23. From inside the castle
From inside a castle's walls, soldiers had a somewhat restricted selection of weapons to use to defend their lord and his fortress.
In addition to arrows, the garrison frequently threw down stone missiles, crushing invaders.
They also relied upon "Greek fire", a volatile combination of petroleum and oil and other natural products, which generated a highly flammable substance that burned on water and was excruciatingly hot.
Apparently, Greek fire was used to make incendiary arrows, but could also be blown through tubes.

24. From inside the castle
The 13th century saw the modification of swords, which could then rend a knight's protective armour.
Short stabbing daggers were also used, as were a variety of axes (some of which were equipped with spikes), clubs, maces, spears, crossbows, and the sling.
The most significant development of weapons technology during this century was the longbow, mastered by the Welsh decades earlier.

25. THE BALLISTA
The ballista was, in effect, a very large, very powerful crossbow usually mounted on a tower, on the castle wall, or in the hoarding. 
To use it, a soldier would wind back a winch using a crank, take aim by swivelling it on the mount, and pull the trigger mechanism releasing the tension on the rope and firing. 
Ballistae were generally used against advancing infantry during a siege. 
The ballista fired a wooden dart, about five feet long with brass flights to keep it's firing trajectory straight and an iron head to penetrate armour

26. Destroy the Castle
The trebuchet was one of the most devastating weapons of the Middle Ages.
Using trial and error, medieval engineers adjusted the trebuchet to make sure its missile hit the castle wall—and destroyed it.
NOVA's science game, "Destroy the Castle," is very much like the real thing. There are five elements you can adjust in your trebuchet:
stone ball weight
sling length
counterweight design
distance from the castle
whether to add wheels
Build it right, and you will crush the wall.
Build it wrong, though, and you may have to face some painful consequences.

27. How Your Trebuchet Works
How you design your trebuchet will decide the fate of the castle wall—and it may also decide your fate as well.
With some choices, your missile might land too short or fly too far.
With others, your missile may hit the castle wall, but not with the force necessary to destroy it.
With an even more unfortunate combination, your launched ball will land on your head or an arrow may pierce your medieval heart.
To learn how your design choices will influence the results of your attack, read these explanations:

28. Wheels/No Wheels
When modern engineers looked at medieval drawings of trebuchets, they found they often had wheels.
They thought that the wheels were added to roll the weapon around the landscape and to help aim it. But when they began to build these life-sized models, they realized that they were too heavy to roll on medieval roads, much less battlefields.
They also noticed something else: those with wheels could fire much farther than their stuck-in-the-mud cousins. They believe medieval engineers discovered the same thing.
Why is a trebuchet with wheels more stable and powerful than those without?
One of the design flaws of the wheel-less trebuchet is its tendency to rear up into the air as its arm begins to spin and then slam back down. This lurch can destroy the trebuchet completely
Rolling wheels stop this occurring. Instead, energy is channelled into the trebuchet's arm and missile.
Wheels add power as the trebuchet rolls forward. Like a bowler in cricket who leans forwards as he bowls, the forward motion adds extra speed to the ball. A higher speed results in a farther throw.

29. Sling Length
When the sling was added to the trebuchet it gave the tossed projectile more velocity.
This meant the trebuchet could send a lighter projectile farther, providing more distance between those who fired the machines and deadly enemy archers at the castle.
Here's how it works. The sling lies on a track at the base of the trebuchet.
As the arm of the trebuchet begins to move, the sling drags the ball before lifting it into the air. This gives the swinging arm time to pick up speed.
The sling is an extension of the beam's reach.

30. Sling Length
At the time it is launched, the sling is actually moving faster than the beam, creating a whipping motion. A faster flung stone will deliver a stronger punch to the wall.
With the extra velocity (which can be converted into a longer throw), the trebuchet can also be moved back to a safer distance from the castle wall.
There's an important catch, however.
If a sling is used to extend the range of a trebuchet, a lighter ball must be used to reach the wall. But remember that light is not good, when you are attacking stone walls!

31. Ball Weight
Provided with the same amount of energy, lighter balls launched from a trebuchet will fly farther than heavier ones.
This makes sense in our everyday experience: Using the same arm, you can throw a tennis ball quite a bit farther than you can a cricket ball, for example.
However, the ball's weight affects more than the distance it will fly.
A lighter ball travelling at the same velocity as a heavier ball will land with less force.
That's why some of the lighter stone balls launched in our trebuchet simulation hit the mark, yet bounce off harmlessly.
The stone's mass is not great enough to break through the sturdy castle wall.

32. Ball Weight
With too heavy a ball, you may suffer the same fate as you wished to inflict upon your enemy:
The ball could fly straight up and back down.
That's because your trebuchet cannot provide enough energy to counteract the pull of gravity that holds your heavy ball down.
There is danger, as well, in erring in the direction of too light a ball.
Too light a ball might not be able to accept all the energy that the trebuchet's swinging arm can deliver.
Where does the energy go?
It may go into the trebuchet's axle pivot, its base, or into its scaffolding, destroying your trebuchet rather than the enemy castle's wall.

33. Distance
How far from the castle you situate your trebuchet matters for a few reasons.
The closer the trebuchet, the more likely you are to hit your target.
However, the opposite is also true, which is that the closer you are, the more likely it is that enemy soldiers will hit you—with an arrow.
The farther away your trebuchet, the farther you'll have to send your missile.
And the farther your missile must travel, the longer the force of gravity will be pulling on its flight.
To counteract gravity's steady pull, you must convey more energy to the ball. Can you see how you might do this?

34. Distance
There is another solution, which is to reduce the weight of your ball as you move it farther away.
A lighter ball will travel farther because there is less mass to move.
However, a problem arises when this principle is taken too far.
A lighter ball will hit with a weaker force than a heavier one.
The result could be a stone dud that bounces harmlessly off the castle wall.

35. Counterweight
The most important design improvements that medieval engineers in the design of its counterweight.
They understood the use of "the seesaw effect" of a lever.
As gravity pulls a heavier weight down on one side of the seesaw, the lighter weight on the other side of the seesaw's fulcrum is lifted.
If the object on one side falls with great force, the one on the other side might become airborne.
When military designers created one arm longer than the other and raised the axle high above the ground, they had built their first functioning trebuchet.
But how did these military men maximize the downward pull of the short arm? The answer: They added literally tons of weight.

36. Counterweight
During the siege against the Scots castle of Stirling, Edward I of England sent orders out to strip all of the church roofs in the entire surrounding area of lead.
These gathered sheets of lead were believed to have been melted down and then attached to the counterweight of the trebuchet.
The most efficient way for any counterweight to respond to the force of gravity is by falling in a straight line.
The hinged counterweight, however, is free to follow a straighter descent to the ground, providing the trebuchet—and eventually the launched stone ball—with an even more devastating power.

37. Homework - It says:
Try out various combinations – hopefully at least one will hit the castle! Underline your choices before you fire. Then type in what happened – and if it did not work, why do you think it went wrong? Write your answer on the ‘Because’ line.
Even if you manage it, why did it work in the ‘Because’ line.
If you are lucky enough to hit the target in less than 4 goes, there is more than one solution – see if you can find another one?
If you manage it the message will be:
The winning message is ‘ Congratulations, you have smashed the castle wall’