The Pantheon (meaning 'temple of every god') is a former Roman temple, now a church, on the site of an earlier temple commissioned by Marcus Agrippa during the reign of Augustus (27 BC-14 AD). The present building was completed by the emperor Hadrian and probably dedicated about 126 AD. He retained Agrippa's original inscription, which has confused its date of construction as the original Pantheon burnt down so it is not certain when the present one was built.
The building is circular with a portico of large granite Corinthian columns under a pediment. A rectangular vestibule links the porch to the rotunda, which is under a coffered concrete dome, with a central opening (oculus) to the sky. Almost two thousand years after it was built, the Pantheon's dome is still the world's largest unreinforced concrete dome. The height to the oculus and the diameter of the interior circle are the same, 43.3 metres.
Pantheon is one of the best-preserved of all Ancient Roman buildings. The Pantheon's large circular domed cella, with a conventional temple portico front, is 'unique' in Roman architecture. Nevertheless, it became a standard exemplar when classical styles were revived, and has been copied many times by modern architects.
Pantheon was converted into the church of St. Mary of the Martyrs in 608 CE. In 1270 a bell tower was added to the porch roof and later removed. Also, at some time in the Middle Ages the left side of the porch was damaged which necessitated the replacement of three columns. The first came from Domitian's villa at Castelgandolfo and was added in 1626. The other two columns came from the Baths of Nero and were added in 1666. However, these additions were rose-pink in colour whilst originally the front eight columns of the porch were all grey and only the internal four were pink Aswan. Also in 1626 Pope Urban VIII removed all of the bronze girders from the porch roof and recast the metal into 80 canons for the city's Castel Sant'Angelo. The presence of these girders suggests that the porch roof originally had heavy marble tiles.
Despite these changes the Pantheon is one of the best preserved ancient monuments in the world and it still has an important function and status today as within it are the tombs of the Italian monarchy from 1870-1946 and another notable tomb is that of Raphael (1483-1520 CE).
Pantheon is visited by over 6 million people annually. It is part of the UNESCO World Heritage Site Historic Centre of Rome.
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.