Geeraard de Duivelsteen is a Gothic building in Ghent, Belgium. It served as defense of the Portus Ganda, the city's port. The building was built in the 13th century and was named after the knight Geeraard Vilain (1210-1270), second son of the fifteenth viscount of Gent, Zeger III of Ghent. Vilain's nickname was Geeraard de Duivel ('Geerard the Devil'), which was based on his dark complexion and hair color.
In the 14th century the building became city property. Over the course of centuries it was used for various functions; gatherings of knights, as an armory, a monastery, a school, a bishop's seminary, an insane asylum and a prison. In 1775 the Rasphuis near the Coupure channel became the new prison. In 1830 the Geeraard de Duivelsteen became a fire station. Near the end of the 19th century it was bought by the Belgian state to serve as a national archive. For this purpose a new wing was built. Due to the numerous restorations the building has changed a lot since the Middle Ages.
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.