When a great lord of the land decided to defend his property and people against invaders, he often built a castle for that purpose. The castle was a tough structure, best built of stone but sometimes out of wood. They usually had high, thick walls to keep out enemies, and places along those walls from which defenders could fire their weapons at attackers. If an invader wanted to take the land, they had to get past the castle first.
How Castles Were Built
There were many ways to build a castle, but some worked better at keeping out enemies than others.
Early castles were made in the motte and bailey style. These castles weren't very strong. They were made of wood and very small. But they could be built in just a few weeks where strong stone castles took years, even decades to build.
In a motte and bailey design, the main living and working area of the castle is surrounded by a wooden fence which is in turn surrounded by a ditch or moat. The main gate of this bailey sometimes had a drawbridge over the moat. Next to the bailey was the motte, the real fortress. The defenders retreated to the motte when things got really bad. The motte was built on top of a tall mound to make it hard to get at. A tower was built in the middle of the motte, then surrounded by a wooden fence.
As time went on, the newcomers would improve their castle. Wooden walls were replaced by stone ones. The fortress might be replaced with a stronger stone building. Towers might be built along the walls.
If the land being protected by the soldiers was important enough, and if the lord in charge had enough money, a stone castle would replace the motte and bailey construction. These full-blown castles were expensive and took many years to build, but they were rarely attacked successfully by the enemy.
Motte and bailey castles were built when an army first came to a possibly hostile area. They were quickly constructed and gave some small protection to the soldiers inside.
The Parts of a Castle
STABLES: Where the horses of knights were kept while the castle was under attack
KITCHEN: Where the meals were cooked.
GREAT HALL: The main dining and meeting building in the castle.
OUTER WARD: The space between the outer curtain wall and the inner curtain wall. If an enemy managed to break through the outer curtain wall, they would have to cross the outer ward to continue their attack. This was certain suicide, as the defenders would be shooting at them the whole time from the towers and crenelations of the inner curtain wall. The path from the outer gatehouse to the inner gatehouse was never a straight line. That way, the attackers would have to move across the front of the inner curtain wall to reach the inner gatehouse, all the time being shot at by the defenders.
OUTER CURTAIN WALL: This was the outer wall of the castle, the first one an enemy would go up against. It was a high wall of concrete faced with stone on both sides. It had a gatehouse that may have been the only way into the castle and was heavily defended. It also had towers projecting at all corners (often more), and would have been surrounded by a moat.
APARTMENTS: Where the soldiers and others running the castle lived. The lord of the castle and his family lived in one of the towers of the inner curtain.
INNER CURTAIN WALL: This wall was taller and thicker than the outer wall. It also had its gatehouse, its crenelations and its projecting towers for defense.
GATEHOUSE: This was one or two towers on each side of the gate in the outer curtain wall or inner curtain wall. The gatehouse guarded these entrances to the castle, and was heavily defended. Defenders could rain arrows or stones down on attackers in many different ways from the gatehouse. This was also where the controls for the drawbridge would be.
To defend against attackers, castles had archers who would shoot the enemy from a distance. Of course, it was necessary to protect the castle's archers from the archers of the attacker. To allow the archers protection while they shot, arrow loops were used. An arrow loop is a very skinny "window" through the wall or tower.
From outside the castle (where the attacker is), the arrow loop is just a thin line of a window. There is an archer back there shooting at you through the arrow loop, but there is nothing you can do about it because your archers are not nearly good enough to put an arrow through that tiny hole.
From inside the castle, it's another story. The arrow loop is still a thin slit of a window, but your archer gets to stand right up next to it, maybe even put the point of his arrow through the loop before he fires. The opening widens out so that the archer can move from side to side and see most of the ground before him. He can shoot from many different angles without fear of being shot himself.
Drawbridges were invented to keep out attackers. First you surround your castle with a moat, which is a pit often filled with water. Then you build a bridge over the moat so that you can cross in and out of the castle. The trick is to make the bridge retractable, to make it so that you can remove the bridge whenever an attacker wants to enter your castle. If you remove the bridge, your enemy must find another, harder way in. And they can't just knock down your door because they can't get past the moat.
Building a drawbridge is simple. You build a flat platform that goes over the moat. You put extra weight on the castle side of this platform. That way, the end near the castle always wants to hang down.
When you want to use the bridge, you place supports under the castle side of the platform so that it won't drop down. When an attacker comes, you remove the supports, allowing the castle side of the platform to drop, which raises the other end of the bridge away from the moat.
It was easy raising the drawbridge, but it was a chore putting it back down.
Towers were built into the corners of curtain walls. These towers were made to project outwards from the wall so that defenders could see all along the wall to shoot at attackers. Windows in the walls and towers were very narrow near the bottom so that no enemy could climb through into the castle. Defenders could shoot from the windows and from the top of the towers. The picture below shows some of the basic parts to a castle tower.
MERLONS: The stone part of the crenelations that stands up. They protected defenders from enemy fire.
EMBRASURES: The low part of the crenelations. Defenders could watch and fire upon enemies through these openings.
CRENELATIONS: This is the top of the tower, the part that looks something like a crown worn by a king. Defenders could shoot at attackers past the embrasures in the crenelations, and hide behind the merlons when the enemy shot back.
ARROW LOOP: A slit window in the tower through which defenders could shoot attackers without fear of being fired upon themselves. Arrow loops would face every approach to the castle.
Inside a tower was at least four levels. The top level was the ARMORY, where weapons were stored for the defenders.
Below the armory was the living area for the lord and his family, or for other important visitors. The windows would have been barred with iron and would have had heavy wooden shutters in case of attack. Still, the living area would be high enough in the tower that it was unlikely any enemy could reach it.
Below the living area was a storage room where food and other supplies were kept at all times in case of attack. A castle could not afford to be caught without food. An enemy's first act was to cut off supplies of food when he laid siege to the castle, so the defenders could last only as long as their storage did.
Below all this was the DUNGEON. The dungeon was where prisoners were kept.
All these levels were reached by winding stone stairs. The winding stairs made it easier for defenders to fight running battles within the tower. Because the curve of the stairs kept more than just a few attackers able to fight the stair defenders at a time, defenders could protect those living in the tower for a longer time than if the stairs were straight and arrows could be brought into play.
Castle Manzaneres in Spain shows many of the parts of a medieval castle. Castles also had windows, as you can see in the inner curtain wall. But wide windows like these were kept to the upper parts of the walls and towers. Windows closer to the ground were very narrow to prevent enemies from entering through them.