A motte-and-bailey castle is thought to have previously occupied the site of Llawhaden Castle and the present structure was built by the bishops of the Diocese of St David in the 13th century. The castle was abandoned in the 16th century and some of the stone was removed for local building projects. The site is privately owned by the Lord of the Manor of Llawhaden and managed by Cadw.
The remaining ruins date from the early 13th century. It is surrounded by a ditch, which was designed to be only crossable by a drawbridge. The castle is pentagonal in shape and while the north-western and western sides of the castle are no longer present, the other three sides remain. The gatehouse is located on the southern side, which is formed of two drum towers and a gateway. This was also where the drawbridge would have been located to allow entrance to the interior of the castle.
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.