Arévalo Castle, locally known as Castillo de Arévalo, lies in a village with the same name, in the north of the province of Avila in Spain.
I do not know when the first castle at this site, on the confluence of the Adaja and Arevalillo rivers, was built but there must have been one in the 14th century when King Pedro I, the Cruel, locked up his wife, Doña Blanco de Bourbon, in it. In 1462 the possession of the castle, together with the title of Duke, was given to Don Alvaro de Zuñiga, count of Plasencia, by King Enrique IV. Don Alvarez got these as a reward for his loyalty. Don Alvarez is the builder of the castle we see today. When he died the castle passed again into royal possession. During the reign of the Catholic Kings Isabel and Fernando (15th/16th century), the castle became (as did many others) a state prison. Various Spanish nobles have been incarcerated in its walls and also a Dutch Prince, Philip William of Orange-Nassau has been a prisoner here in the 16th century.
The ground plan is almost square, round towers at its corners, round sentry boxes on its walls and the large D-shaped keep in one corner. The keep is made of ashlar masonry with later brick additions similar to the rest of the castle. Also the castle underwent changes to adapt it for its role as a prison in the 16th century and was upgraded for the use of firearms. As you can see traces of connecting walls on the right side of the keep and the left side of the left wall, I think that the castle was a part of the village ramparts in medieval times.
After its use as a prison was over the castle fell to ruin and it got to be used as a cemetery. In the 1950's the castle was restored by the Ministry of Agriculture, turned into a cereal silo for a short while and was later taken into use as a museum. What its present use is I don't know. The castle was closed when I visited and there were no signs of any sort. It's a very nice castle, especially the keep.