The Clementinum

This vast Baroque complex, the second largest in Prague after the castle, covers almost two hectares in the heart of the Old Town. From 1227 there was a Dominican friary here dedicated to St Clement, which the Hussites burned down in 1420. Its name outlived everything else.

1The Jesuits arrive

On 21 April 1556 the first twelve Jesuits arrived from Rome, invited by Ferdinand I of Habsburg. In a largely Protestant Bohemia, their college was a forward post: free, high-quality teaching, theatre and science, and at the same time a tool to bring the country back to Catholicism. After the imperial victory of 1620 the Jesuits took over the university founded by Charles IV, and the Clementinum became the intellectual heart of the Counter-Reformation.

When the Swedes tried to cross the bridge in 1648, students and professors from this college helped defend the barricade at the tower. The Pope dissolved the order in 1773, and the building passed to the university and later to the library.

2Prague's weather station

In the Astronomical Tower, built in 1722, weather data have been taken systematically since 1752 and without interruption since 1775, when Antonín Strnad began recording them. It is the longest continuous series in Central Europe. Today the complex houses the National Library of the Czech Republic.

3What to look for

• The statue of Atlas carrying the celestial sphere at the top of the Astronomical Tower.
• The Church of St Saviour, on the corner with Knights of the Cross Square, with its columned portico and statues.
• The sheer length of the facade on Karlova: walk it and you will grasp how powerful the order became.