By the 12th century, the lords of Waldsdorf had established their seat on the site of the present stately home in the shape of a fortified manor house with a large dairy farm. From 1315 to 1605 it was owned by the noble family of Windisch-Graetz. In 1563 major conversion and renovation work was carried out on the castle under the then-owner and designer, Erasmus of Windisch-Graetz, which saw it expanded into a Renaissance style stately home with a courtyard surrounded on three sides by three-storey high, columnar arcades. There is still an underground passage, dating to that period, that runs as far as Graz, but it is impassable after the first several hundred metres.