Drysllwyn Castle stands on high ground overlooking the Tywi Valley with extensive views. It was built in about the 1220s by one of the princes of the kingdom of Deheubarth, and changed hands several times in the struggles between the Welsh and English over the ensuing centuries. It is considered one of the most important remaining structures built by a Welsh chieftain.
Drysllwyn was seized by Owain Glyndŵr in the summer of 1403 and when the English forces recaptured it they decommissioned it by blocking various access routes, walling up the gatehouse, removing the treads from stone stairs and even removing the hinges from the main gate. At some later stage, all the major buildings were burned to the ground. Following this a lot of the stone was removed from the site
The polygonal Inner Ward contains principal remains to the south west, with traces of the Middle and Outer Ward to the north east. The early thirteenth century curtain wall to the Inner Ward only stands 1m high. There is a garderobe to the east side, and a remodelled thirteenth century Gatehouse to the north east, surviving at foundation level only. On the south side of the Gatehouse is the Round Tower, the original keep. The foundations of the original Great Hall and Rhys ap Maredudd's hall survive.
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.