Its defining elements include crenellation and rusticated stone. They were usually topped with crenellation or parapets that offered protection to defenders. They are so named because they somewhat resemble the crenellation on medieval castles. They are conical heavy masonry bastions with a crenellation band running at the top level. The outermost secondary border often has reciprocal crenellation patterns. The crenellation of the parapet dates from the restoration work carried out in the 1980s. There, the Ogle's manor house was licensed for crenellation in 1341. Crenellation on the inner walls around the courtyard is of the stepped type. The characteristic Scottish designs of crow-stepped gables and the battlement crenellation elements were introduced. Crenellation crowns the arches, and is also carved in stucco. The act of adding crenels to a previously unbroken parapet is termed crenellation.