The Rotunda of the Holy Cross is the oldest Romanesque rotunda in Prague. It was built in the 11th century. The first mention of the Rotunda of the Holy Cross is from 1365, but it was probably built already at the end of the 11th century. It is a small simple building with a rounded nave and an apse. A lantern at the cupola has a gilt cross, a crescent moon and an eight-pointed star at the top.
Rotunda of the Holy Cross was probably a private chapel belonging to some of the mansions in Prague Old Town. There used to be a parsonage nearby and a cemetery around.
Dominicans gained the rotunda in 1625. Emperor Joseph II. abolished the chapel in 1784, as well as many other churches, and it became a private storage. It was planned to demolish the rotunda in 1860 because of building a new house at the place, but it was finally saved.
There are remains of Gothic wall paintings from 14 th century inside. The most valuable Gothic fresco is the “Three Magi veneration”. There are also some remains of tombstones from 13 th century.
The legend about the origin of the rotunda says, that there used to be a lake at the place originally. A crucified girl, punished for her Christian belief, was thrown there with her cross. The cross reared up during a storm, which was regarded as a God´s sign. A large dozy cross was really found in the foundations of the rotunda, when it was restored.
References: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.