Things You'll Need
Instructions
Build four squares that are 8 by 8 studs. Make sure the outside edges of the squares align. These will act as the towers that reside at each corner of the castle. Build a square through the middle of these four towers that will act as the walls of the castle. Leave an opening in the middle of one of the walls that will be the door.
Build more layers on the top of the existing base, overlapping the connection between the bricks below to create a solid wall. Build the wall as high as you want to, but don't make it too high, because it might look out of proportion.
Build in floors of the towers with the 2 by 4 bricks. Make the floor two studs larger on all sides as the walls of the towers and castle wall. This will let you build a walkway along the walls and platforms on the towers.
Build one more layer around the newly-expanded edges of the wall and tower. Then go through and place a 2 by 2 brick every four studs, to create the crenelations that top most castles and castle walls. This is as far as you need to go for the basics of a medieval castle.