Our Lady's Church (Vår Frue kirke) was erected around the year 1200. The victim of many fires, it was restored in 1739, but parts of the thick, solid walls of the Church are obviously much older. The first tower of the church was built around 1640, but the current tower was built in 1742 and the spire was erected in 1779. However, the eastern part of church (to the right in the picture) is identical to the 'Church of Our Mary' from the end of the 12th century.
The Baroque style altar dates from 1744 and rococo pulpit from 1771. There are also chandeliers from the 17th and 18th centuries. On the church wall you can see Runes which were carved into the stone 800 years ago.
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.