A defensive brick building in Jarocin, defined in a 1496 document as a fortalitium, had presumably already been erected by the beginning of the 15th century. This building was then rebuilt, extended and eventually demolished. The building known locally as skarbczyk (the jewel box) is all that remains of it today. A lot of decorative fragments of Gothic furnace tiles, attesting a once opulent castle interior, have been uncovered here during the course of excavation work.
There is a two-storey brick and plaster building laid out on a rectangular plan and surrounded by what used to be moats by the pond in the southern part of the park. The domed turret adjoining the body of the building from the west was added a good while later. The main body has a tiled pitched roof. The walls are supported by strong corner abutments and framed rectangular window openings. A stone bas-relief of the Leszczyc coat of arms of the Radoliński family hangs above the portal on the tower elevation. The vaulted rooms inside have been preserved.
It is now the Jarocin branch of the Regional Museum.
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.