"It was a fortress of no great size, consisting of a donjon, or large and high square tower, surrounded by buildings of inferior height, which were encircled by an inner court-yard. Around the exterior wall was a deep moat, supplied with water from a neighbouring rivulet. Front-de-Boeuf, whose character placed him often at feud with his enemies, had made considerable additions to the strength of his castle, by building towers upon the outward wall, so as to flank it at every angle. The access, as usual in castles of the period, lay through an arched barbican, or outwork, which was terminated and defended by a small turret at each corner."
Sir Walter Scott "Ivanhoe".