Holt castle was started by Edward I on a sandstone base next to the River Dee soon after the invasion of North Wales in 1277. In 1282 Edward presented the Welsh lands of Bromfield and Yale in which Holt was situated to loyal lord John de Warrene, who was also given the task of completing the castle. By 1311 the castle had been finished and a planned town laid out next to it for the use of English settlers.
A century later, Welsh forces burned down the town in 1400 during the uprising of Owain Glyndŵr; although the castle was not taken. By the 16th century Holt Castle had fallen into disuse and ruin.
For most of the First English Civil War, Holt was garrisoned by Royalists troops. It was captured by the Parliamentarians in 1643 but retaken by the Royalists in spring of 1644. After they had surrendered, thirteen of the Parliamentarian garrison were put to the sword and their bodies were thrown into the moat. In January 1647, after a siege that lasted for nine months the Royalist governor, Sir Richard Lloyd, surrendered Holt to Thomas Mytton (the commander of the besieging Parliamentarians).
Between 1675 and 1683 much of the castle was taken away by Sir Thomas Grosvenor, 3rd Baronet of Eaton, who used barges to carry the stonework downstream to rebuild Eaton Hall after the English Civil War.
In the 18th century all that remained of Holt Castle was part of a tower and a rectangular building.
The only sizeable part of Holt Castle that remains is perched on its sandstone base. Some masonry features are still visible, including the lower walls of the inner keep, the postern gate, a buttress, a chute exit and the foundations of the outer gate's square tower.
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.