In the Late Middle Ages and Early Modern Period, two castle buildings stood on the southern slope of the Dobrča Mountain between Tržič and the village of Begunje which have been in ruins for centuries. The article discusses their architectural history. The Gutenberg Castle was built around the mid-twelfth century as a Romanesque fortification. Until the early sixteenth century, it was expanded several times and converted into a picturesque articulated fortification architecture. The castle was abandoned after the earthquake in 1511 and in 1557 its name was transferred to the neighbouring medieval Glanz tower house, which was built as a residential tower in the second half of the thirteenth century or in the fourteenth century. In the fifteenth century, the Glanz tower house was expanded into a small fortified medieval castle. After the earthquake in 1511, between 1531 and 1558, it was thoroughly reconstructed, expanded, and converted into a Renaissance country mansion for Baron Jacob III of Lamberg. Due to its poor accessibility, the Glanz castle complex was already abandoned in the first half of the seventeenth century.