Under the Aosta old parish church, archaeological diggings brought to light the early Christian cruciform basilica, indicated as Concilium Sanctorum, the Assembly of Saints because it was built on the tombs of some of the early martyrs who were buried in the Roman cemetery area which in itself was built on a protohistoric funeral settlement.
Inside you can see parts of the liturgical structures, the relic platform with the tombs of three bishops who lived between the 5th and 6th centuries (Grato, Agnello, Gallo) and other tomb chambers dating from between the 5th and 8th centuries.
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.