First mentioned as Soban, Sobień Castle was a Royal castle guarding the merchant route along the San River. The castle was built by order of King Casimir the Great in 1340. In 1389 Władysław II Jagiełło conferred the castle to a noble family of Kmita.
The castle was destroyed in 1474 and again in 1512 by Hungarian forces. In 16th century the Kmita family sold the estates and the castle to Stadnicki family, who held it until 1713.
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.