San Andrés is a church in the parish of Bedriñana. It dates to the 9th century and was declared a national monument in 1931. The nave was built in the tenth century. Four of the original windows above the nave survive. Significant additional expansion occurred in the 12th-13th centuries and again in the 16th. In 1916, additional improvements were made to the building for use as a school.
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.