The construction of the Niebla Castle started in 1402, when Don Enrique de Guzmán, the second Duke of Medinasidonia and the fourth of Niebla, pulled down the old Moorish Alcázar to build the one we know today. The result was a magnificent royal palace which preserved the most interesting and luxurious parts built by the Arabs, such as the Muslim Tower of Homage.
After the works of restoration made in the last few years, the Alcázar is now in good conditions. It has a rectangular structure divided by an inner wall which separates the patio of arms from the luxurious rooms intended as palace. This main structure has ten towers; six of them are square (four are on the corners -including the Tower of Homage - and two of them are at the ends of the inner wall). The other four are semicircular cubes alternated with the square ones. The walls go on from the Tower of Homage and the one located on the north-west angle to form a barbican surrounding the central building on the east, south and west sides. This barbican has six towers and joins the almohade wall near the Puerta de Sevilla and del Socorro. An adarve and a barbican built in the late 15th century completed the building.
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.