The Castello di Naro was built on top of a hill in the 14th century by the Chiaramonte family. The complex includes walls with battlements, a square tower built by Frederick II of Aragon and the imposing 'mass of the male'. On the east side there are two mullioned Gothic windows that illuminate the great 'Hall of the Prince', which is located on the first floor of the tower. The portal is flanked by two rectangular bastions. The massive outer walls are interspersed with two cylindrical towers and two square towers.
Inside the walls there is a large courtyard, which housed the accommodation of the garrison, the chapel and the stables, and in the case of attack offered refuge to local farmers.
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.