Arcos de Jalón Castle, dating from the 14th century, stands on the site of an old Arab fortress. It was besieged in the 14th century by the supporters of the Castilian King Pedro I, who fought against the rebel D. Fernán Gómez de Albornoz, supporter of his bastard brother Enrique de Trastamara.
This castle has a rectangular floor plan although it is quite irregular due to the fact that it adapts to the rugged land of a high and narrow hill that divides the town into two parts. A robust keep is attached to the castle walls which are made of thick stonework, horizontal brick rows and ashlar with stonecutter’s marks on the corners. There is only one entrance which is located high up and two loophole windows.
Inside there are remains of the structures that divided the tower, which once was taller, into different floors, and all throughout the perimeter, you can see where the foundation walls began and some towers that reinforced the structure.
This fortress is so unique due to the double-lined brick walls, a technique that mainly had a structural purpose, but has also given the castle beautiful reddish lines between the stonework. This construction method has a clear Mudejar origin which was most likely influenced by the amount of Muslims in the village and in the area of Aragon.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.