Carnuntum was a Roman Legionary Fortress and also headquarters of the Pannonian fleet from 50 AD. After the 1st century it was capital of the Pannonia Superior province. It also became a large city of 50,000 inhabitants. In Roman times Carnuntum had a history as a major trading centre for amber, brought from the north to traders who sold it in Italy; the main arm of the Amber Road crossed the Danube at Carnuntum. Its impressive remains are situated on the Danube in Lower Austria in the Carnuntum Archaeological Park extending over an area of 10 km² near today's villages of Petronell-Carnuntum and Bad Deutsch-Altenburg.
The remains of the civilian city extend around the village Petronell-Carnuntum. There are several places to see in the city: Roman city quarter in the open-air museum, palace ruins, amphitheatre, and Heidentor.
Some way outside the city was a large amphitheatre, which had room for about 15,000 spectators. A plate with an inscription found at the site claims that this building was the 4th largest amphitheatre in the whole Roman Empire.
Between 354 AD and 361 AD, Heidentor, a huge triumphal monument was erected next to the camp and city. Contemporary reports suggest that Emperor Constantius II had it built to commemorate his victories. When the remains of Carnuntum disappeared after the Migration Period the monument remained as an isolated building in a natural landscape and led Medieval people to believe it was the tomb of a pagan giant. Hence, they called it Heidentor (pagan gate).
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.