The Bonn Minster (Bonner Münster) is one of Germany's oldest churches, having been built between the 11th and 13th centuries. At one point the church served as the cathedral for the Archbishopric of Cologne.
Castra Bonnensia was a fortress on the site of current Bonn built by the Romans in the 1st century AD. It survived the breakup of the Roman Empire as a civilian settlement, and in the 9th century it became the Frankish town of Bonnburg.
Around 235 AD, two Christian Roman soldiers stationed in Castra Bonnensia, Cassius and Florentius, were martyred for their faith. Tradition has it that a small memorial shrine was built over their graves in the 4th century by St. Helen, mother of Constantine. There is no surviving evidence of this first structure, but archaeological excavations have shown that the basilica stands on the site of a Roman temple and necropolis.
The original memorial hall was expanded into a larger church in the 6th and 7th centuries, and many people were buried near the martyrs inside and outside the building. Further extensions were carried out in the 8th century.
Around 1050 the church was demolished and construction began on the present Romanesque building, which dates from the 11th to 13th centuries. By the end of this period Bonn had grown in importance, becoming the capital of the Electorate and Archbishopric of Cologne, which was then a sovereign state. The new basilica appeared in the city's coat of arms. In 1643, Cassius and Florentius were officially declared the patron saints of the city of Bonn.
The basilica suffered significant damage in 1583-89, 1689, and in World War II, but each time it was fully restored. In 1956, the Bonner Münster was granted the status of Papal Minor Basilica.
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.