St. Catherine Church has undergone numerous changes over the centuries. It was originally built around the end of the 13th century, in the Occitan Gothic style; several 13th century features remain, such as the holy water stoup. It formed part of the defensive system of town walls and was at the entrance to the village.
During the Wars of Religion in the 16th century, the building was badly damaged, and the church bells were thrown into a well (but they were later retrieved and one was able to be restored).
It was re-roofed and restored during the reign of Henry IV (1589-1610).
Each century since has seen intermittent efforts to restore and improve the church, including a major re-orientation of the building in 1876.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.