Schloss Seggau is located on a wooded hill overlooking the town of Leibnitz. The area around Schloss Seggau has been settled since at least the Roman era, as demonstrated by the impressive lapidarium which has survived from that period. The upper castle was built by the Archbishopric of Salzburg in the twelfth century as a base for missions and supervision and this original structure was expanded in 1218 by the bishops of Seckau. Over time, a total of three castles were built: Burg Leibnitz (belonging to the Archbishopric of Salzburg), the castle of the bishops of Seckau, and Schloss Polheim. The castles were completed in their present form under Bishop Johann Ernst, Count of Thun, in the latter half of the seventeenth century. Schloss Seggau was the residence of the bishops until 1786, after which it remained their summer residence until into the twentieth century.
Schloss Seggau now serves as a site for seminars and conferences with a hotel and a Schloss Cafe. The wine cellar is over three hundred years old and offers the opportunity for wine tastings and sales.
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.