San Marcos is a Gothic church in Jerez de la Frontera. It originates from one of the six parishes founded by King Alfonso X of Castile after his conquest of the city in 1264. The current edifice was likely started in the mid-14th century, due to the style of its polygonal apse and the Mudéjar portal, perhaps above a pre-existing mosque. The construction is anyway not documented until the middle of the 15th century, including a substantial renovation in late Gothic style.
The church has three façades, with a main entrance portal in Mannerist style (16th century). The interior has a Baroque high altar (18th century)
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.