Järlåsa Church has had at least two predecessors. The earliest one was a medieval stone church whose ruins still remains c. 500 metres north of the church. At some point it was replaced with a wooden church, which was however in such a bad shape in the 17th century that it was replaced with the presently visible, octagonal church and demolished in the early 18th century.
The church may have been designed by Nicodemus Tessin the Elder; it was built at the initiative of Baron Gustaf Rosenhane, who is documented with having employed Tessin for other building projects. The main, octagonal church building was built 1672-1688 and inaugurated on 29 June 1688, while the church porch wasn't finished until 1704. Originally the sacristy was a wooden annex but it was replaced with a stone structure in 1766–68.
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.