Karlštejn Castle: The Complete Guide to the Most Famous Castle in Bohemia

A Karlštejn Castle day trip from Prague is one of the most rewarding half-days in Bohemia — and one of the easiest. Thirty kilometres southwest of the city, the castle appears suddenly above the trees: a dramatic Gothic silhouette on a limestone cliff above the Berounka River, looking exactly as a medieval imperial fortress should look.

But Karlštejn is more than a beautiful castle. It was built to house the most precious objects in the Holy Roman Empire — the Crown Jewels, the Imperial Regalia, and Emperor Charles IV's extraordinary private collection of holy relics. Understanding what was kept here, and why, transforms a visit from a pleasant excursion into something genuinely memorable.

Here is everything you need to know before you go.

Why Charles IV built Karlštejn

The castle was founded on 10 June 1348 by Charles IV — King of Bohemia and Holy Roman Emperor — and the name says everything: Karlstein means "Charles's Stone" in German. Construction was completed in 1365. Charles personally supervised every detail of the interior decoration, treating the castle not as a residence but as a sacred repository for the most precious objects in his empire.

What was so precious? The Imperial Regalia of the Holy Roman Empire. The Bohemian Crown Jewels. And Charles's extraordinary private collection of holy relics — pieces of the True Cross, fragments of saints, sacred objects from across Christendom that he had spent a lifetime assembling.

To house the most sacred of these, he built the Chapel of the Holy Cross inside the Great Tower — a room secured behind multiple iron doors and locks, its walls lined with 129 panel paintings by Master Theodoric, court painter of Charles IV. This is the largest collection of medieval panel paintings in the world, and one of the greatest achievements of Gothic art in Central Europe.

The castle that held for seven months

Karlštejn was built to be impregnable — and it proved it. The castle's stepped layout reflects the medieval hierarchy of power and holiness: three levels rising one above the other, each more sacred and more secure than the last. The Imperial Palace at the base. The Marian Tower with the Church of the Virgin Mary and the Chapel of St. Catherine. And at the very summit, the Great Tower with the Chapel of the Holy Cross at its heart.

During the Hussite Wars of the 1420s, the castle withstood a siege that lasted more than seven months. Hussite attackers even resorted to catapulting dead bodies over the walls in an attempt to spread disease. The castle held. The Bohemian Crown Jewels remained safe within its walls for nearly 200 years.

After 1619, when the Bohemian Crown Jewels were permanently moved to Prague, the castle gradually lost its significance and fell into disrepair. The Gothic Revival restoration carried out by architect Josef Mocker between 1887 and 1899 gave the castle its current appearance — the dramatic, fairy-tale silhouette that makes Karlštejn one of the most photographed places in Bohemia.