Tårnborg Castle was a royal medieval castle. It consisted of a central tower of 8m x 8m, surrounded by a square outer wall. An excavation in the castle courtyard in 1894 also revealed the remains of three small houses. The castle stood from about 1231 up to the last part of the 14th century when a new castle in Korsør took over Tårnborg's role. From written sources we know that the castle was captured several times, once in 1326 when King Christopher II’s son was forced to submit to the rebellious troops after a two-week siege.
References:Celje Castle was once the largest fortification on Slovenian territory. The first fortified building on the site (a Romanesque palace) was built in the first half of the 13th century by the Counts of Heunburg from Carinthia on the stony outcrop on the western side of the ridge where the castle stands. It had five sides, or four plus the southern side, which was a natural defence. The first written records of the castle date back to between 1125 and 1137; it was probably built by Count Gunter. In the western section of the castle, there was a building with several floors. Remains of the walls of this palatium have survived. In the eastern section, there was an enclosed courtyard with large water reservoirs. The eastern wall, which protects the castle from its most exposed side, was around three metres thicker than the rest of the curtain wall. The wall was topped with a parapet and protected walkway.