The oldest parts of Alva Church are the choir and the apse, dating from the early 13th century. To this the nave was added during the late part of the same century. Construction of the broad tower started about a hundred years later but was never finished; hence the somewhat squat appearance of the church today. It seems in fact that construction of the church came to a rapid end: apart from the half-finished tower, the main southern portal also seems to have been finished in a haphazard, chaotic way.
The choir portal is Romanesque in style and carried some sculpted reliefs, possibly executed by the locally active Master Sigraf. The likewise Romanesque northern portal of the church is also decorated with sculptures.
Inside, the church displays a set of frescos carried out at the end of the Middle Ages, probably just before the reformation and possibly by the same artist who decorated Lau Church. Among the furnishings, the dominating triumphal cross, dating from the middle of the 13th century, and a partly preserved baptismal font, executed by the Romanesque master carver Hegvald sometime during the end of the 12th century, are especially notable. The pulpit dates from 1740 and the unusually decorated altarpiece from 1653. The church was renovated in 1953-54.
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.