Nostra Segnora de Mesumundu is located in the archaeological complex with the same name. It was built in the 6th century, during the Byzantine domination of the island, over a pre-existing Roman structure (2nd century AD). The Byzantines re-used part of the walls of the Roman building, as well as the aqueduct. The edifice could have been used as a baptistery. However, it is also possible that it was used for the purification of ill people through an immersion rite.
In 1063, the structure was donated by the Giudice (duke) Barisone I of Torres to the Abbey of Montecassino. When monks came from the Italian religious community, they adapted the building for Roman Catholic use, adding an apse and a new entrance (demolished in 1934). For the work, they used materials from the nearby Roman ruins and the nuraghe Culzu.
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.