The origins of Gesualdo Castle can be traced back to the Middle Ages during the Lombard conquests in southern Italy in the 7th century. It was founded either by the legendary Knight Sessualdo or by Radelchi, Prince of Benevento, as a defensive outpost. The first documented records date back to the 12th century under Norman rule, with William of Altavilla as the first lord. The castle gained importance during the Norman-Swabian era and became a prominent fortress in the region.
Carlo Gesualdo, a descendant of the Norman line, transformed the castle into a Renaissance-style mansion in the late 15th century. Over the centuries, the castle suffered damage and looting during various conflicts, including the Franco-Spanish War and the arrival of French troops in 1799. It underwent significant renovations in the 19th century and was designated as a site of historical and artistic value in 1913. The castle was severely damaged in the 1980 Irpinia earthquake and has undergone ongoing restoration efforts. Currently, a portion of the castle is open to the public, and future plans include establishing a polyphony education high school within its premises.
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.