Originally built in the 11th century, when the Normans fought the Byzantine rulers in Southern Italy, the Corigliano Calabro Castle expanded in the first half of the 1300s thanks to the powerful Sanseverino family. In the 15th century, the castle was renovated and its architecture took on the typical features of the Aragonese style; the structure was further altered in the 17th century by the Saluzzo family, and in the 19th century by the Compagna family.
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.