Okoř is a castle on a low rocky promontory in Okoř, north-west of Prague, about 15 kilometres from the city centre. In 1228 a stronghold was built in the small hamlet of Okoř. It was later modified into a Gothic castle, founded in 1359 by Frantisek Rokyčansky, a wealthy burgher of Prague's Old Town. It was later modified by comprehensive Late Gothic remodelling by the Lords of Donin. In 1518, during the reign of Bořitas of Martinice, the castle was turned into a residence in the Renaissance style.
During the Thirty Years' War the castle was heavily damaged and then restored in the Baroque style. It underwent further extension in the second half of the 15th century, and in the 17th century it was owned by Jesuits. Following their departure after the Jesuit order was discontinued in Bohemia, the Okoř castle became deserted in the late 18th century and slowly began to deteriorate.
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.