The Mezquita was built from a visigothic basilica from the 5th century, reusing its materials, and is one of the few surviving Spanish rural mosques.
It is an oddly-shaped building, made of brick and stone in a trapezoid shape, probably because of the hilly terrain. The oration room has 5 naves, whose arches, like in the Mezquita in Cordoba, are perpendicular to Qibla. The central nave is wider than the 2 nearby, which are in turn wider than the 2 outer naves. The Mihrab has lost its paint, and looks quite archaic; only the brick and stone is visible. In the oration room, 16 undated tombs were found.
When Spain became Christian, many changes were made, including the addition of a central axis in accordance with the new religion. The old door and the North flank were also reconstructed. Despite these changes, the whole building still retains a rustic charm.
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.