A hillside castle is a castle built on the side of a hill above much of the surrounding terrain but below the summit itself. It is thus a type of hill castle and emerged in Europe in the second half of the 11th century. As a result of the particular danger to the site from attacks on the castle from the rising ground above it, this weak point is usually strongly protected by a shield wall or a Bergfried. Often a combination of these two passive defensive works were used.