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:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.