The Svibno Castle was first mentioned around 1175; it has been built by the Dukes of Spanheim and managed by their liegemen, the Lords of Svibno. During the Middle Ages the castle has been managed by the noble Svibno family, the liegemen of the Counts of Korosko-Kranjska. The most famous among them was Viljem Ostrovrhar, who died in the battle of Grebinj in 1293, when he took part in a mutiny against his sovereign. The castle scheme, well-known from detailed descriptions and old graphics made by the 17th century historian, polymath and a member of the British Royal Geographical Society Janez Vajkard Valvasor, is nowadays hardly recognizable. In the ground configuration it is still possible to surmise the blockades, which blocked the path to the castle. The remains of a palace yard tower, an outer cistern and circumferential walls are still preserved, while the castle core can only be noticed from the outlines. The ruins of Svibno Castle are located on a steep precipitous rock called Ostri vrh (643 m) on top of Grajski hrib (Castle Hill) with the St. Cross's Church (Cerkev Sv. Kriza) and the village of Svibno just below. Unique location guarantees superb views on Sopota Valley and the nearby mountain Kum. The end of May is the time when kranjski sebenik blossoms on the Castle Hill. In 1826 a doctor from Vienna, George Dolliner, made a botanical journey to his homeland, to his hometown Radece. On the slopes of a dolomitic Castle Hill just above Svibno Village George Dolliner found a yellow violet (sebenik) and recognized it as a new species. He named it kranjski sebenik after the province that Radece belonged to during those times. It is now known that kranjski sebenik can also be found at the Zasavska Sveta gora and Gorjanci. Find out more about Radece at http://www.ktrc.si