white castle occupies a hill near the village of llantilio crossenny, overlooking the surrounding landscape. the castle dates mainly from the 13th century and is made up of a central inner ward, a crescent-shaped hornwork to the south, and an outer ward to the north, with its stonework constructed from red sandstone. the outer ward was originally much larger, extending around the castle further to the east, but only limited traces of these earthworks survive. it is now entered from the north-east although, prior to the 13th century, the castle 's entrance was originally on the south side. the historian paul remfry considers the castle to be "a masterpiece of military engineering" for the period.