Paint the walls to resemble stones. Measure off squares or rectangles on the walls and paint in a sand or gray color. Outline the squares with a darker color to give a stone appearance to the walls.
Install stonelike tile on the floors. Match the color to the selected faux stone walls.
Install large, thick wooden or iron doors. This type of door protected wealthy castle owners from invasion.
Lay large rugs on the floor. In the old world, wall-to-wall carpeting was not common, but large woven rugs were used by the wealthy.
Install a fireplace. Old world castles' only source of heat was fireplaces. These fireplaces were large and sometimes the focal point of the room. Paint a faux fireplace on the wall if installation is not possible.
Use large, wooden furniture. Depending on the regional look you are going for, many castles were decorated with wooden block furniture.
Hang wrought iron chandeliers and wall sconces. These were the source of light for old world castles.
Decorate the walls with large portraits, landscapes or religious art.
Hang draperies or cover windows with wooden shutters. Wooden shutters prevented invaders from entering the windows. Draperies were a sign of wealth in the old world.