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 Château de Foix dominates the town of Foix. An important tourist site, it is known as a centre of the Cathars. Built on an older 7th-century fortification, the castle is known from 987. In 1002, it was mentioned in the will of Roger I, Count of Carcassonne, who bequeathed the fortress to his youngest child, Bernard. In effect, the family ruling over the region were installed here which allowed them to control access to the upper Ariège valley and to keep surveillance from this strategic point over the lower land, protected behind impregnable walls.
In 1034, the castle became capital of the County of Foix and played a decisive role in medieval military history. During the two following centuries, the castle was home to Counts with shining personalities who became the soul of the Occitan resistance during the crusade against the Albigensians.