The oldest parts of Gerum Church are the choir and apse, dating from circa 1200 and Romanesque in style. The presently visible, Gothic nave dates from a later time of the 13th century and probably replaced an earlier, Romanesque nave. The tower, which was never finished, was built circa 1300. The only non-medieval part of the church is the sacristy, built in 1835.
Gerum Church is constructed of limestone. The exterior is whitewashed apart from several finely carved stone details. The façade is broken by four windows on the southern side while the northern completely lacks windows. The church has three portals, one Romanesque in the choir and two Gothic in the nave and tower, respectively. The Gothic portals are decorated with stone sculptures. Inside, the church carries frescos from at least three different periods: the 13th century, the 15th century (by the Master of the Passion of Christ) and the 18th century. The church also has a decorated stained glass window from the 14th century.
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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.