Saint Peter’s (Saint-Pierre) church was formerly an abbey church of the Benedictines. The abbey church was founded in the 7th century with the help of Queen Bathilde, the wife of Clovis II. The most important vestige of the church is a convent buildings located on the south side, later rebuilt in early 18th century, and nowadays served as a school named Lycee Marceau.
The church was destroyed several times by Normans between 858 and 911. It has also been damaged by fire in 1077 and 1134. Reconstruction of the apse and ambulatory has taken in 1165 under the direction of Bilduard with less financial support. The tomb of Gilduin, a bishop of Breton, who died in 1077 and buried in the church was discovered during the work. This discovery encouraged donations from the congregations and allowed the continuation of the reconstruction of the church and also supported the construction of Chartres cathedral tour and royal portal.
The most ancient part of the church is the bell tower on the west side, built around the year 1000 AD. The nave and the aisles date from the early 13th century. The church was finally completed around the year 1320. During French revolution, the church has seized and served as a saltpeter factory - then finally returned to its original function as a worship place in 1803 and nowadays regularly host the Organ Festival. St. Peter’s church opens from Monday to Friday at 2pm to 6pm and you can enter the church for free.
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.