Bogenšperk Castle (Wagensperg) is one of the most important Renaissance castle buildings in central Slovenia and at the same time one of the key locations of Slovenian scientific, cultural, and cartographic history. It was built in the 16th century on a low hill southeast of Šmartno pri Litiji, where it still stands today at an altitude of 412 meters. Its prominence is inseparably linked with Janez Vajkard Valvasor, an exceptional 17th-century polymath and member of the London Royal Society, who created the most significant part of his life's work right here at Bogenšperk.
The current appearance of the castle is the result of several centuries of transformations. The three-story building is designed in four wings that surround an arched inner courtyard and connect four towers from different periods. The oldest among them is the north tower, which was initially a standalone fortification. Later, it was connected by a wooden bridge to the southeast tower, once the highest and most distinctively defensive part of the complex. A fire caused by a lightning strike in 1759 severely damaged the tower, which is why it was never restored to its original height.
In its current form, the castle was most likely started by the noble Wagen family, who needed a new residence as their original Lichtenberg Castle was in decay and further damaged by the 1511 earthquake. After the extinction of the Wagen family in 1630, Bogenšperk passed from hand to hand until it was purchased by Valvasor in 1672.
Valvasor thoroughly renovated the castle and transformed it into one of the most advanced scientific centers of its time. In it, he arranged:
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a graphic studio,
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a printing house,
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a rich library,
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a cabinet of curiosities,
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a surveying and cartographic laboratory.
It was at Bogenšperk that the monumental The Glory of the Duchy of Carniola was created, a work that propelled Valvasor into the European intellectual space. Although the costs of publication financially exhausted him, forcing him to first sell his library and then the entire estate in 1692.
After Valvasor's departure, the castle again frequently changed owners. Among them were members of the Erberg, Lichtenberg, Jungwirth, and finally Windischgrätz families, who definitively left it in 1943. During World War II, the interior furnishings almost completely disappeared, but the building itself remained undamaged. After the war, a military hospital was arranged in it, and from 1957, Jesuits operated in the castle, taking care of basic maintenance.
In 1972, a comprehensive and professionally led renovation began under the direction of art historian Milan Železnik, which returned the Renaissance appearance to the castle and enabled its museum and cultural revival.
Today, Bogenšperk is an important museum center, primarily dedicated to Valvasor's life and work. Among the most important contents are:
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Valvasor's Graphic Workshop – a reconstruction of his graphic and printing studio, which brings 17th-century copperplate engraving and printing techniques closer to visitors.
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The Slovenian Geodetic Collection – established at the castle in 1987 in cooperation with the Technical Museum of Slovenia, it remained there until 2021. The collection represented the development of Slovenian cartography, geodesy, and measuring instruments, with a special emphasis on Valvasor's pioneering work.
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Permanent Exhibitions about Valvasor – showcasing his life, scientific achievements, membership in the Royal Society, and the creation of The Glory of the Duchy of Carniola.
Today, Bogenšperk Castle is:
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a cultural monument of national importance,
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a museum complex,
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a venue for weddings, concerts, lectures, and cultural events,
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a center of local identity and tourism.
For the municipality of Šmartno pri Litiji, it represents one of the key development points. The castle attracts visitors from Slovenia and abroad, strengthening the region's recognition and encouraging the local economy. 
Visualization of Bogenšperk Castle - 17th century (www.mojaslovenija.si)
The Slovenian Geodetic Collection at Bogenšperk during the period 1987-2021
Valvasor's Graphic Workshop during the period 1980-2021
Valvasor's View of Nature