Like many churches in Friesland, St. Martin's Church was built on a terp, a heightened piece of land to protect whatever was on it from floods. Several churches had been standing on this spot before this one, although the terp had been at least two metres lower when the first church was built. The current church dates from the early 15th century and was named St. Martinus until the Reformation of 1580, when it was conficated for protestant use. Although it also served as a pilgrims church in memory of St. Boniface, who had been murdered nearby in the year 754.
Originally St. Martin was a one-aisled building in Gothic style. The northern side-aisle was added in the late-16th century and has round-topped windows. For the construction of this side-aisle stones were used of the abbey-church that was demolished in 1589 as a result of the Reformation, and that had been standing next to this church. The facade of the original aisle has a stepped gable, a 20th-century reconstruction of an old situation as known from old drawings. At the back, built directly against the choir, is a consistory with a facade dating from 1734.
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.