The Clementinum (in Czech Klementinum) is a building constructed in 1556 by Ferdinand I in Prague, in an attempt to restore Catholicism in the Czech Republic. The Clementinum houses the oldest Jesuit church in Prague, the Convent of Saint Clement, which gives its name to the entire building.
The Clementinum became a secular university and Empress Maria Theresa declared the Jesuit library as the Imperial Regia Biblioteca Universitaria. In 1882, Charles University was divided into two separate institutions, one for the Czech language and the other for the German language: the Clementinum was assigned to the Czech faculty of philosophy and theology. Starting from 1930, the Clementinum remained solely the library of the faculty.
In 1918, the newly formed Czechoslovak Republic took possession of the library, which became the National Library. It houses documents related to Mozart, Tycho Brahe, and Comenius, as well as the history of Czech literature.
The Clementinum continues to host the Prague Clementinum meteorological observatory.
