Tretower Castle is a Grade I-listed ruined castle in the village of Tretower. It was founded as a motte and bailey castle by Picard, a follower of Bernard de Neufmarché. Probably around 1150, Picard's son, Roger Picard I, replaced the motte with a shell keep. By about 1230 a tall cylindrical keep was added to the inside of the shell keep, possibly by his great-grandson, Roger Picard II, and the space between was roofed over. At this time the earlier bailey was walled in stone and provided with cylindrical corner towers. In the early 14th century residential buildings were constructed away from the original fortifications forming today's Tretower Court. Over time the lords of Tretower favoured the more luxurious Court and the castle fell into disuse.
The castle is roughly triangular in plan, with the motte and keep assemblage occupying the western corner. The 12th century shell-keep is an irregular enclosure with a gate-tower on the line of approach from the bailey. In the centre of the shell stands the tall cylindrical 13th century keep. The keep is of three storeys, with an original entrance at first floor level, above a strong, slanted batter or talus. The top of the talus is marked by a decorative string-course of stone.
References:The Gravensteen is a castle in Ghent originating from the Middle Ages. The name means 'castle of the counts' in Dutch. Arnulf I (918–965), Count of Flanders, was the first to fortify this place, building a medieval bastion on this high sand dune, naturally protected by the river Leie and its marshy banks. This bastion consisted of a central wooden building and several surrounding buildings, also in wood.
In the early 11th century, the wooden building was replaced by a stone residence, consisting of three large halls that made up three storeys, connected by a stone stairwell. The monumental stone staircase, the light openings, the fireplaces built into the walls and the latrines were signs of considerable luxury and comfort in those days. There was probably also a tower.