St. Clement's Church or Klemet's Church was one of the Roman Catholic parish churches of the old Oslo. It was a stone church with a tower, and it was one of the very few churches we know with the double-nave floor plan. Along the middle axis of the choir there were three powerful pillars that held the roof. The church went out of use after the Protestant Reformation, and expect it rather quickly was in ruins.
The church was exposed and examined through excavation by arcitect Johan Adolf Gerhard Fischer in 1921. Then remained for years unnoticed during Loeng bridge. In 1970-71 was archaeologist Ole Egil Eide opportunity to dig further into the ground under the church, and found traces of burials older than the stone church, 81 in all. His interpretation is that there have been at least two churches, presumably stave churches, on the spot where the stone church was built around 1100. The oldest of the graves are dated to the radiological 980-1030, and were some of the oldest Christian burials found in Norway. Ruins of Clement's Church is now exposed and is included as part of Middelalderparken in the Old Town of Oslo.
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.