The Dubovac Castle overlooks the Croatian city Karlovac. Its square tower was probably built during the 13th century. In the 15th century, the castle was rebuilt in Renaissance style. The castle had various owners—from Slavonian nobleman family Sudar to famous Croatian counts and dukes Frankopan and Zrinski. From 1671 until 1809, the Dubovac was owned by the Karlovac generals. In 1837, a new owner, Count Laval Nugent, rebuilt the castle in the spirit of romanticism. Dubovac was once again renovated in 1952 in relation to graphics from the end of the 18th century.' There is a photograph of the castle at that site.
The castle was used for several years recently as a hotel, and the damage done to the interior to accommodate rooms is now being repaired. There are museum exhibits and a large model of the countryside. Guide materials indicate that the fortress was built on a hill constructed by the people in order to maximize defenses and views of the surrounding areas.
The castle recently was featured on a commemorative Croatian postage stamp, complete with photograph.
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.