The Church of Saint Sofia is an Eastern Orthodox church in Nesebar, eastern Bulgaria It is situated in the old quarter of the town which is part of the UNESCO World Heritage Site list and of the 100 Tourist Sites of Bulgaria.
The church is located in what is supposed to have been the center of the ancient city. It is a three-naved unvaulted basilica with a semi-circular apse, a narthex and an atrium. The church has a total length of 25.5 m and a width of 13 m. The division into three naves was effected by two rows of five pillars each. The middle nave ends to the east with a big closed apse, round outside and three-sided inside. There are three arched windows on the eastern wall above the apse. The basilica used to have a double-sloped roof which has not been preserved. From the inside the church used to be plastered and then painted with frescoes. The whole floor used to be covered with mosaics made out with little coloured stones. It has mixed masonry of stone and brick and is the largest of the Nesebar churches whose overground structure has survived.
The basilica was constructed in the late 5th and early 6th century. Its present appearance was dated from the beginning of the 9th century when it was reconstructed. During the Middle Ages it served as a cathedral for the bishopric eparchy centered in Nesebar. In 1257 the church was looted by the Venetians during a campaign against the Bulgarian Empire and many religious relics were taken in the Church of San Salvatore in Venice. The basilica was abandoned in the 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.