Estepa castle was known in the Islamic period as Hisn Istabba, and was taken by Spanish king Fernando III on 15 August 1241.
The city walls that still surround the old town on the San Cristóbal hill were first built in the tenth century by the Moors, renovated by Almohad invaders in the twelfth, and again reconstructed when Estepa fell to the Christian Order of Santiago in the thirteenth century. The keep inside the walls was built against attacks from Granada in the fourteenth century, and at 26 metres offers sweeping views of the town and surrounding countryside.
A defensive tower built by Lorenzo Suárez de Figueroa, Master of Santiago, it carried out defensive and logistical functions, measuring 26 metres high by 13 metres wide. On clear days, you can see Sierra Nevada from the roof.
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.