Rhuddlan Castle was erected by Edward I in 1277, following the First Welsh War. The castle was completed prior to the rebellion of Llywelyn the Last in 1282. The remains of older Norman castle at Twthill, built in 1086, is just to the south of the current castle.
In 1294 the castle was attacked during the Welsh rising but was not taken. It was attacked again in the by forces of Owain Glyndŵr in 1400. This time the town was badly damaged but the castle held out. In the latter 15th and early 16th centuries the castle's condition deteriorated as its strategic and administrative importance waned.
Rhuddlan Castle was again garrisoned by Royalist troops during the English Civil War, and remained a stronghold of King Charles I of England until well after the Battle of Naseby, being taken by Parliamentary forces under Thomas Mytton after a siege in 1646. Two years later, Parliamentarians partially demolished the castle to prevent any further military use. By the time Pennant passed through in 1781, it was largely ruined.
Rhuddlan was planned as a concentric castle. It has a unique 'diamond' in layout as the gatehouses are positioned at the corners of the square baileys instead of along the sides like at Flint, Harlech or Beaumaris. Records of construction costs show that it was the major piece of building work being carried out by the English during the late 1270s.
The inner ward has defensive walls with twin-tower gatehouses. The outer ward is surrounded by a curtain wall that has small towers and turrets. The castle had a three-sided moat, with the River Clwyd protecting its fourth side. Within the inner ward there was a great hall, kitchens, private apartments and a chapel. The outer bailey had a granary, stables and a smithy.
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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.