because they wanted to
Arrow slits in the walls and rooms.
If I had to defend a castle then I would either build the walls stronger so catapults or other modern day objects Can not get through the Walls of the castle or make the castle higher so the stones or other objects cant get over the Wall's.
you would need about 99 people to build a castle.
castles were used for defence and it protected the people inside the castle an example of a defensive castle would be carrickfergus castle. Major defence points were portcullis, murder holes, arrow slits ect.
If they had a defensive wall (castle wall) they would most likely have archers. The archers would then shot the enemy if they would try to attack the castle. Does that answer you're question?
If it is a concentric castle, then it would have a set of outer walls and inner walls. Basically, the name is outer walls, if you were asking for the proper terminology. If you're inquiring towards their use, outer walls are thinner than inner walls and their purpose is to provide a space between the inner and outer walls from which attackers may be stopped before reaching the castle.
well they would have guards that would pour burning oil onto attacking troops and they would have slits that archers would fire arrows at the troops hope this helps
sand.
On a hill!!
a long time!!
Mining the walls was the process of digging under the castle walls to remove their support so they would fall down.
To defend their territory. and impose a point of power.