Religious ceremonies and celebrations, many of which were organized, stood out by their glamorous pretentiousness. The plan was to build a Catholic university, as a rival to Charles University. The splendour and momentum of their building activities adequately served the order’s mission.
Of all the Jesuit buildings, the Clementinum is the largest. The original Dominican monastery expanded into a monument covering 19 hectares, on the site where 32 residential houses used to be. The Saint Clement Church was rebuilt from its foundation. Schools and dormitories were constructed, Vlasská Chapel was founded. A section with a theatre hall and the Mirror Chapel with its library hall arose. A residential house with the meteorological observatory was added and also the Church of the Holy Saviour (Kostel svatého Spasitele) was built. The grounds of the Clementinum are bordered by Seminárská ulice, Karlova ulice, Krizovnická ulice, Platnérská ulice and Mariánské námestí.
One can enter the yard through three gates. One gate is in Karlova ulice, a second in Krizovnická ulice and a third in Mariánské námestí. The Clementinum is a remarkable building and an artistic monument, to which many great architects of late Renaissance and the Baroque period contributed – for example Carlo Luraga, Francesco Carratti, Dominic Orsi, F. M. Kanka and others. Within its walls is the National Library with 6 million items and a large collection of manuscripts and first editions. The University Library, which is its core, appeared in the time of Emperor Charles IV. The first catalogue of manuscripts dates from the year 1370. In the grounds of the Clementinum is also the Technical Library. It contains valuable documentation about the technical developments of the last two hundred years. The Mirror Chapel was converted into a concert and exhibition hall.