The Church of Saint Michael started its life in the end of the 15th century. A plaque at the door of its Gothic facade is dated 1484. It is believed that the church was commissioned by the Catholic Monarchs when they visited the city in 1484. Previously, the area was served by an old hermitage. Its construction, however, would last several centuries resulting in an excellent cathedral-like set where latest gothic elements and other ones typical from beginning and full renaissance and baroque.
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.