Uncastillo Castle lies, in a village by the same name, in the province of Zaragoza in Spain.
The village of Uncastillo sprawls in concentric circles around a large flat rock with sheer, vertical sides; called Ayllón. On the flat top of this rock there is some 6600 square meters of space, in the shape of an irregular oval of about 115 by 75 meters. There are several vestiges of walls but nothing else that remains from the 10th or 11th century. Because in 921 it was known as 'Unuh Qastil', a Muslim fortification.
In 1033 it was integrated in the Kingdom of Aragon and it became known as 'Unum Castrum'. It was an important Aragonese border castle and protected the lands against the nearby Kingdom of Navarre. Although its importance it was a primitive castle with a single tower. The space on top of the rock was divided by a, now disappeared, wall into a larger and a smaller area. On the furthest edge of the smaller area, which was slightly higher, stood the square keep, we see today, dominating the village. Its dimensions are about 10x10 meters and it has 3 stories. Around 1356 the dividing wall was partly torn down to build a small Gothic mansion. It has a rectangular groundplan and had 2 stories, the upper one reached by a spiral staircase in a small, graceful, octagonal tower. It then became known as 'Uno Castello'.
The war of Succession however, in the 14th century, left the castle dismantled, with reduced outer walls, the ruined single tower and the small ruined Gothic mansion.
In the 20th century the keep was partially reconstructed. Surprisingly, there is a nice little museum in the keep and you can climb up on the top of the keep. The village itself is also very nice to visit; there are several old Gothic buildings. In recent years the Gothic mansion has also been partially restored.