The oldest known church on the site was built in the 13th century. The medieval church was demolished in 1854 and replaced with a new one designed by Sven Sjöholm and J. A. Hawerman. This church was destroyed by lightning in 1943. The present church was built in 1946-1947.
The medieval font and altarpiece (painted in the mid-19th century) have survived. The other interior date from 1940s.
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.