Clementinum

• 1. Introduction

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  In a 1943 short story called "The Secret Miracle," Jorge Luis Borges places his protagonist inside a dream of the Clementinum, where librarians search through four hundred thousand books looking for the letter that contains God. One of them says: "My fathers and the fathers of my fathers have looked for this letter; I myself have gone blind looking for it." That image, of endless human searching inside a single grand building, captures something essential about the Clementinum in Prague. It is a complex covering 20,000 square metres, the second largest concentration of buildings in the city after Prague Castle. Its history stretches back to an 11th-century chapel, running through wars, religious orders, imperial decrees, and the birth of a nation. The questions worth sitting with are: how does a chapel become a Jesuit college, a Jesuit college become an observatory, and an observatory become the home of a national library? And what does it mean that, somewhere along the way, this place also hosted what is claimed to be the first World's Fair?

• 2. From Chapel to Jesuit College

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  A chapel dedicated to Saint Clement stood on this site as far back as the 11th century. Around that foundation, a Dominican monastery grew during the medieval period. The monastery was heavily damaged in 1420 during the Hussite Wars, those violent religious conflicts that reshaped Bohemia. More than a century later, in 1556, the site was transformed into a Jesuit college, a change that would define the complex for the next two hundred years. The Jesuits moved quickly to consolidate intellectual authority. In 1622, they transferred the library of Charles University to the Clementinum, pulling the university's scholarly resources into their orbit. Thirty-two years after that, in 1654, the Jesuit college was formally merged with the University itself. At its height, the Clementinum was known as the third largest Jesuit college in the world. The main building campaign that gave the complex its current scale took place between 1709 and 1726, a period that produced the Baroque library at its heart.

• 3. The Baroque Interior

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  The Baroque library hall built during the 1709-1726 campaign is the architectural centrepiece of the Clementinum today. Its ceiling carries artwork by Jan Hiebl, a painter whose work depicts the medieval understanding of human knowledge. The ceiling functions as a visual map of how educated Europeans of that era organized what they knew. Since 2023, Prague City Tourism, a company owned by the City of Prague, has run a baroque route through the Clementinum that takes visitors through this library hall and up the Astronomical Tower. The Jesuits who commissioned this interior remained in residence until 1773, when they were suppressed across the Habsburg Empire and beyond. It was at that point that Empress Maria Theresa of Austria stepped in and reconstituted the Clementinum as an observatory, a library, and a university all at once.

• 4. Observatory, Archives, and a Remarkable Exhibition

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  The weather station established at the Clementinum in 1775 is among the oldest continuous meteorological records in Central Europe. Readings begun in that year have continued without interruption to the present day, giving scientists an unbroken span of atmospheric data stretching across more than two and a half centuries. The National Library was formally founded in 1781, and from 1782 the Clementinum became a legal deposit library, meaning publishers were required to submit copies of their works there. Then, in 1791, something happened at this site that had no precedent: the Clementinum hosted what is described as the first World's Fair. The occasion was the coronation of Leopold II as king of Bohemia, and the industrial exhibition mounted alongside it was designed to demonstrate the sophistication of manufacturing in Czech lands at the time. That combination of scholarly archive and public spectacle points to the range of purposes this single complex has served.

• 5. National Library and the Mozartiana Collection

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  When the Czecho-Slovak state was established in 1918, it took over the library that had been operating under imperial authority. Since 1990, the institution has carried its current name: the National Library of the Czech Republic. The collection held inside includes Mozartiana, materials related to the astronomer Tycho Brahe, works connected to the educational reformer Comenius, and historic examples of Czech literature. In 2005, the Czech National Library received the UNESCO Jikji Prize, part of the Memory of the World programme, recognizing the significance of what is preserved there. Until recently the complex also housed the National, University, and Technical libraries together. In 2009, the Technical Library relocated to the Prague National Technical Library at Technická 6, and the Municipal Library operates in the adjacent building on Mariánské Náměstí, where the Idiom installation, known as the book tower, stands in the foyer.

• 6. The Question of Expansion

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  For several years before 2006, city and library authorities debated what to do about a building complex that was running out of room. Space in the Clementinum was expected to reach its limit by 2010. On the 10th of January 2006, Prague authorities decided to sell city-owned property in the Letná area to the National Library as the site for a future building. That spring, an international architectural design competition was launched. The architect Jan Kaplický won that competition. The decision was later overruled, and the Czech National Library has remained without a confirmed final project for its expansion. The Clementinum itself carries on: a complex that began as a single 11th-century chapel, grew through war and religious transformation, and today holds the books, maps, and manuscripts that a national culture uses to remember itself.