This charming square was named after the church that dominates the whole quarter. It is a gothic church, longitudinal with high prismatic tower. Built in 14th century on the site of the previous Romanesque church it was modified in the second half of 17th century - its upper parts were remodelled in Baroque style according to designs by architect Pavel Ignác Bayer.
Interestingly, the prominent Czech painter Josef Mánes was baptized in this church in May 1820. Noteworthy is also the fact that consecration of the church in honour of Saint Castul is rather rare in central Europe. This saint lived in 3rd century in the court of Emperor Diocletianus. He hid Christians in his home at the time of persecution, however, betrayed, he died a martyr’s death. The picturesque building No. 789, north of the church is of the previous vicarage and of gothic origin.
Fragment of Krocínova fountain, which used to stand in the Old Town Square, is immured in the outer wall. This is a valuable fragment of the previous Haštalská quarter, today used by Orthodox Catholic Church. Another building worth of note, is house No. 1041, in the eastern part of the square, is a former charnel-house. This is a remarkable building that belonged to cemetery, which was previously spreading over part of the square. Visit the square to enhance the atmosphere of old Prague and stroll in the little streets that lead from the square in all directions.