Kosmonosy Castle

Kosmonosy Castle sits in the small town of Kosmonosy, just a few minutes from Mladá Boleslav in Central Bohemia. It is a modest but layered building — a Renaissance core rebuilt in the Baroque period and later softened with Classicist additions — and today it serves the town as a school rather than a museum piece.

How did the castle at Kosmonosy come about?

The story starts in the second half of the 16th century, when Adam Krajíř of Krajek decided the castle in nearby Mladá Boleslav was too dilapidated and uncomfortable to live in. He moved his residence to Kosmonosy and built a Renaissance stronghold there instead. After his death the original building fell into disrepair, and by the mid-17th century the estate had passed to the Czernin family, who set the rebuilding of the residence in motion.

When did it take on its Baroque form?

The castle's current Baroque shape dates from the turn of the 17th and 18th centuries. Commissioned by the Czernins, the Italian architect Giovanni Battista Alliprandi designed a four-wing layout around a central courtyard — a standard arrangement for aristocratic residences of the period. That Baroque skeleton, despite later alterations, still defines the building's footprint today.

Who owned the castle afterward?

Ownership changed hands several times after the Czernins: the estate passed to the Hrzán of Harasov family, then the Martinic family, and from the late 18th century to the Mirbach family. It was the Mirbachs who, in the 1830s, added a Classicist south wing and laid out an English-style park around the building, softening its earlier, more defensive appearance. The facade was updated again in the early 20th century. In 1932 the town of Kosmonosy bought the castle, and it has housed a school ever since.

Can visitors go inside?

Not really — the building is in active use as a primary school, so there is no regular public tour of the interior. Visitors can, however, walk through the surrounding castle park, which stays open to the public, and view the exterior from the grounds. The castle is listed as a protected cultural monument in the Czech Republic.

What else is worth knowing about Kosmonosy?

In the same town, in a separate complex that once housed a Piarist monastery founded by the Czernin family, a psychiatric hospital has operated since the mid-19th century — one of the oldest in the country. It is a distinct building with no architectural connection to the castle itself, though the two are often mentioned together because the same noble family founded both.

Frequently asked questions

Where exactly is Kosmonosy Castle located? In the town of Kosmonosy, in the Mladá Boleslav district of Central Bohemia, right next to the city of Mladá Boleslav.

Who built the castle? Adam Krajíř of Krajek built the first residence in the second half of the 16th century; its later Baroque form was designed by architect Giovanni Battista Alliprandi for the Czernin family.

Can you go inside the castle? No — the building now houses a primary school, so the interior is closed to visitors. Only the surrounding park remains open to the public.

Is this the same building as the Kosmonosy psychiatric hospital? No. The psychiatric hospital occupies a separate former Piarist monastery complex in the same town — a different building from the castle.

Since when has the town owned the castle? Since 1932, when Kosmonosy purchased the building and turned it into a school, a use that continues today.