Three large monoliths called Harold's Stones are located in a field on the eastern side of the B4293 to the south of Trellech. The stones are on slightly elevated ground close to running water and springs, which might be relevant to the choice of site. They are believed to date back to the Bronze Age. Such remains are rare in this part of Wales. They derive their name from a legend that they mark the spot at which three chieftains fell in battle with Harold Godwinson, who defeated the Welsh in Gwent in 1063. In another legend the stones were flung from Skirrid by the mythical Jack o' Kent in a competition with the Devil.
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.