The Château de Gisors was a key fortress of the Dukes of Normandy in the 11th and 12th centuries. It was intended to defend the Anglo-Norman Vexin territory from the pretensions of the King of France. King William II of England ordered Robert of Bellême to build the first castle at Gisors. The first building work is dated to about 1095, and consisted of a motte, which was enclosed in a spacious courtyard or bailey. Henry I of England, Duke of Normandy, added an octagonal stone keep to the motte.
In 1193 the castle fell into the hands of the King of France and thereafter lost temporarily its importance as a frontier castle. A second keep, cylindrical in shape, called the Prisoner's Tower, was added to the outer wall of the castle at the start of the 13th century, following the French conquest of Normandy. Further reinforcement was added during the Hundred Years' War. In the 16th century, earthen ramparts were built. Since 1862, Château de Gisors has been recognised as a monument historique by the French Ministry of Culture.
Château de Gisors is also known for its links with the Templars. Put into their charge by the French king between 1158 and 1160, it became the final prison of the Grand Master of the Order, Jacques de Molay, in 1314.
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.