St. Peter's Church, once three-naved, was built between 1227 and 1250 and expanded in the 15th and 16th century to a five-naved Gothic hall church. The church roof was destroyed during the Second World War and was provided with an emergency roof in 1960. Reconstruction was only completed in 1987.
Nowadays, St. Peter's is no longer used as a church. Instead, the 800-year-old light and airy church interior has evolved into a vibrant centre for events and exhibitions. A large arts and crafts market takes place here during the Christmas period.
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.