Neither the origins nor the date of construction of San Romualdo Castle is certain, although historians are fairly sure that this castle dates back to medieval times. Built in the Mudéjar style, it was first mentioned in 1268. It is thought to have been used as both convent and fortress.
The castle was officially declared as a historic monument by the Spanish authorities in 1931 and is easily located near the town centre, half way between the town hall and the Zuazo Bridge.
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.