What materials were used to make castles?
Usually from stone, but early motte and baily forts were made of wood. Some fortresses in Eastern Europe were made of brick, since stone is scarce there.
The earliest medieval castles were motte-and-bailey types that had wooden palisades on a hill, either man made or natural, called a motte, and also surrounding an flat open area, called a bailey. Later castles were usually made of stone, though temporary castles continued to be made of wood for some time. In places where there was no stone, castles were sometimes made of brick, and a few such castles still exist.