Church of St Castulus (Kostel sv. Haštala)

The Church of St Castulus is a unique, irregular four-aisle basilica with towers. The church is located approximately at the site of an original Romanesque Hospitaller church which dated back to 1234. Remnants of this Romanesque structure and tombs were found during an archaeological excavation in 1993. The cemetery was located near the church at what is now Haštal Square (Haštalské náměstí).

The Gothic structure is probably from the second quarter of the 14th century. The church has been remodelled and reconstructed several times.

During the Hussite period, the church was administrated by the Utraquist church and it remained in their possession until 1624, when it was taken over by the Catholics. The church burned during the great fire of 1689, when French incendiaries set fire to the Old Town. At the site of the destroyed church, architect Paul Ignaz Bayer started to remodel the church in the Baroque style. Work was completed in 1695.

The interior of the church is modest. The Gothic space, with pillars and rib vaulting in the northern two-aisle section, is one of the finest examples of Prague's Gothic architecture. This section houses a group of Baroque sculptures by Ferdinand Maxmilian Brokoff depicting the Passion of Christ. Gothic murals of the Last Supper and the Crucifixion have been preserved in the sacristy. A painting by Josef Scheiwl adorns the Neo-Renaissance main altar. The exquisite Baroque statues of St John the Baptist and St John of Nepomuk are also the work of Ferdinand Maxmilian Brokoff.

The flood of 2002 caused extensive damage to the church.
The church belongs to the Roman Catholic Church.