Church of Saint Castulus

St. Castulus Church is a quiet, unassuming landmark in Prague's Old Town — and the only church in the entire Czech Republic dedicated to this particular saint. Tucked away near the former Convent of St. Agnes, well off the crowded route between the Old Town Square and the river, it counts among the oldest parish churches in Prague, with roots reaching back centuries before the neighborhood took its present shape.

Where exactly is the church located?

The church stands in the eastern part of Old Town, close to the grounds of the former Poor Clares' convent. This part of the district has kept a residential, low-key feel — narrow streets, few tourists, and none of the souvenir-shop bustle found closer to the Astronomical Clock.

How far back does its history go?

Long before the current building went up, an earlier Romanesque hospital church stood on the same spot, dating back to 1234. It was likely connected to the Knights Hospitaller, an order dedicated to caring for pilgrims and the sick. Traces of that original structure — wall fragments and burial sites — only came to light in 1993, during archaeological work carried out on the parish grounds.

A Gothic rebuild and the Hussite era

The church seen today was built between 1375 and 1399, replacing the older Romanesque structure with a new Gothic design. During the Hussite period, up until 1624, the parish was run by the Utraquists — followers of communion under both kinds, one of the central movements of the Bohemian Reformation. Only after that date did the church pass into Catholic hands.

Fire and a Baroque rebirth

A turning point came with the great fire that swept through Old Town in 1689, set by French agents during the war with the League of Augsburg. The Gothic church was almost entirely destroyed. Its reconstruction was overseen by architect Paul Ignaz Bayer, who gave the building the Baroque appearance it largely still wears today.

What does the architecture look like now?

Centuries of rebuilding left behind an irregular, four-aisled basilica with towers — a rare case of one structure carrying three distinct eras at once: Romanesque foundations, a Gothic body, and Baroque detailing on the facade and interior. That layered building history is exactly what makes St. Castulus Church worth a detour for anyone drawn to Prague's lesser-known religious sites.

Frequently asked questions

Is this really the only church dedicated to St. Castulus in the Czech Republic? Yes — it's the sole church in the country consecrated to this saint, which alone sets it apart on the map of Prague's sacred architecture.

When was the current building constructed? The Gothic core of today's church was built between 1375 and 1399, on the site of an earlier 13th-century Romanesque church.

Why does the church look Baroque rather than Gothic? Because the original Gothic building was largely destroyed in the 1689 fire that devastated Old Town. The reconstruction led by Paul Ignaz Bayer gave it the Baroque form still visible today.

Is the surrounding area worth exploring too? Definitely — the streets near the former Convent of St. Agnes offer a calmer, more local side of Old Town, away from the main tourist routes.