Erstavik estate was first mentioned in 1356 when it was given to Bengt Larsson. It was acquired by Petersen family in the 18th century and his descendants still own the castle. In the Great Northern War 1719 Russian fleet persecuted also Erstavik and several farms were burned down. The current main building is designed by Jean Eric Rehn and it was build in the 1760s. The three-storey house includes an chapel and two wings. interior is well-preserved sample of Rococo and Gustavian style.
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.