Karlstejn - is a large Gothic castle founded 1348 by Charles IV, Holy Roman Emperor-elect and King of Bohemia. The castle served as a place for safekeeping the Imperial Regalia as well as the Bohemian coronation jewels, holy relics and other royal treasures. Located about 30 km southwest of Prague above the village named Karlstejn, it is one of the most famous and most frequently visited castles in the Czech Republic.
The construction of the castle began in 1348 and Matthias of Arras is often credited with being the architect, but he already died in 1352, and then Holy Roman Emperor Charles IV. personally supervised the construction works and the decoration of interiors. The construction was finished nearly twenty years later when the "heart" of the treasury – the Chapel of the Holy Cross situated in the Great tower – was consecrated in 1365. The castle underwent several reconstructions: in late Gothic style after 1480, in Renaissance style in the last quarter of the 16th century. During the Thirty Years' War in 1619, the coronation jewels and the archive were brought to Prague, and in 1620 the castle was turned over to Ferdinand II, Holy Roman Emperor. After having been conquered in 1648 by Swedes, it fell in disrepair.