Monastery of San Pedro de las Dueñas was built in the late 10th century and beginning of the 11th century. It is one of the most representative churches of Mudejar Romanesque in its Pre-classical period, began in stone and finished in brick (1087 and 1110) and Basilical ground plan.
Over the presbytery of the chancel stands a brick tower, it is square with progressively decreasing sections.There is an interesting collection of capitals. The most remarkable of them is the one known as 'de las siete monjas' (the seven nuns capital) and the chancel shows an interesting Christ by Gregorio Fernández.
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.