The ancient city of Ialyssos extended around the hill of Filerimos, which was the ancient acropolis where there are remains of buildings from the Archaic, Byzantine and Knights' periods. The temple of Athena Polias, which dates to the 3rd-2nd centuries BCE, was built over the site of an earlier Classical temple, to judge from from the evidence of a 5th century BC floor and terra-cotta antefixes found there. The depository on the west side produced pottery and votive offerings dating from the 9th to the 5th centuries BC.
In addition to the cult of Athena Polias, in Ialyssos there are also references to a cult of Zeus Polias. In the Early Christian period (5th-6th centuries AD) a three-aisled basilica with an atrium was built on the remains of the ancient temple, in the north aisle of which a single-aisled church with a cupola was constructed in the 10th century.
In the time of the Franks this site was occupied by a medieval monastery and church.
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.