The Kavilda stronghold (Kawelecht) was, according to Leonhard von Stryk, first built in 1354 by Bartholomäus von Tiesenhausen. Other sources say it was built in 1361 by Arnold von Vietinghoff, the Master of Livonian Order. The castle was destroyed during the Livonian War somewhere between 1564 and 1582. It was probably knocked down before the invasion of the Poles. Thereinafter Kavilda excisted only as a manor but not as a castle.
The castel was a castellum-like building with a tower-shaped residential building. Nowadays only one and a half floors have remained, most of it under the ground.
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.