Archaeological investigations suggest an earlier, smaller church may have stood on this site as far back as the 1200s, and Christian burials here appear to predate the present building. Dendrochronological dating of the roof timbers indicates that the current church was raised using timber felled in the winter of 1306-07. It was originally a spacious, tower-less hall church, its walls decorated with paintings and covered by a large timber barrel vault.
A turning point came in 1427, when the vaults were rebuilt under the priest Mathias, inspired by Västerås Cathedral, dividing the church into three narrow, tall aisles carried on ten pillars. The side-aisle vaults were kept deliberately low so as not to obscure the older wall paintings beneath them. The tower and its gothic spire, one of the few of its type surviving in the Västerås area, were rebuilt in the 1660s-70s, along with the Sparfvenfeldt family burial chapel to the south, styled after the royal vault at Riddarholmen Church in Stockholm, its domed roof and coloured walls contrasting with the whitewashed exterior elsewhere.
The church's most striking feature may be its Romanesque wall paintings, uncovered in the 1960s and conserved in 1977. Fragmentary and difficult to interpret, they are inspired by Byzantine art and are described as the only surviving Romanesque wall paintings north of Lake Mälaren; stylistically they appear to date from around the mid-1200s, earlier than the church building itself. A separate, later painting in the porch, from the early 1500s, depicts Saint George and the dragon.
Among the furnishings is a wooden sculpture of the Virgin and Child dating from the early 1300s, possibly connected with the church's original dedication, along with medieval carved doors, a chalice and paten from the late 1300s, and three medieval grave slabs, one commemorating a lawman buried in 1320. A local legend tells of a man who travelled to Rome to raise funds for the church's construction and, on his return, was wrongly executed for theft of the medieval chalice still kept here; he became known as Romfar, giving the church its name, and was venerated locally after his death. Another local figure remembered on a grave slab is Margareta, said to have been murdered in 1507, whose story also became the subject of local legend.
The altarpiece painting of 1769, depicting the Last Supper, is by Louis Masreliez, painted in his twenties and reportedly inspired by Rembrandt's Batavians' oath. The organ, built in 1970 by A. Magnussons Orgelbyggeri, has a case designed by the architect Jörgen Fåk, who also oversaw a broader remodelling of the interior in the 1960s.