St. George's Basilica is the oldest surviving church building within Prague Castle. The basilica was founded by Vratislaus I of Bohemia in 920. It is dedicated to Saint George.
The basilica was substantially enlarged in 973 with the addition of the Benedictine St. George's Abbey. It was rebuilt following a major fire in 1142. The Baroque façade dates from the late 17th century. A Gothic style chapel dedicated to Ludmila of Bohemia holds the tomb of the saint. The shrines of Vratislav and Boleslaus II of Bohemia are also in the basilica. The abbess of this community had the right to crown the Bohemian queens consort.
The building now houses the 19th century Bohemian Art Collection of National Gallery in Prague. It also serves as a concert hall.
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.