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:Rosenborg Palace was built in the period 1606-34 as Christian IV’s summerhouse just outside the ramparts of Copenhagen. Christian IV was very fond of the palace and often stayed at the castle when he resided in Copenhagen, and it was here that he died in 1648. After his death, the palace passed to his son King Frederik III, who together with his queen, Sophie Amalie, carried out several types of modernisation.
The last king who used the place as a residence was Frederik IV, and around 1720, Rosenborg was abandoned in favor of Frederiksborg Palace.Through the 1700s, considerable art treasures were collected at Rosenborg Castle, among other things items from the estates of deceased royalty and from Christiansborg after the fire there in 1794.
Soon the idea of a museum arose, and that was realised in 1833, which is The Royal Danish Collection’s official year of establishment.