The oldest part of the church is the tower, dating from the middle of the 13th century. The nave is from the beginning of the 14th century, while the choir dates from the middle of the same century. There was an earlier church on the same spot, elements of which have been incorporated as building material in the presently visible church. The church is richly decorated inside with frescos dating from the Middle Ages. They depict different Christian motifs. Of the church fittings, the baptismal font (second half of 12th century) and triumphal cross (middle of the 13th century) are both medieval.
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.