The castle itself has origins stretching back some 800 years, and gained its present Renaissance appearance under Gustav Vasa, Erik XIV and Johan III. It was Johan III who, from 1569, converted a residential floor of the castle into a church, finally consecrated in 1592. The interior fittings, however, were not completed until the reign of Gustav II Adolf, and were later altered and added to during the 18th century.
The church room is notable for its decorative, patterned vaulted ceiling, said to be modelled on a castle at Güstrow in northern Germany. The walls and window vaults are decorated with framed verses from the Psalms, adding to the sense of a richly furnished royal chapel rather than a plain parish church.
Among the furnishings, the enclosed box pews with numbered doors give a glimpse of how congregations were once seated according to rank. At the front stand the royal chairs, taller than the ordinary pews, made in 1614 for the royal wedding that was ultimately cancelled because of plague. Their corner posts take the form of metre-high candlesticks decorated with crowns, a striking reminder of the ceremony that was meant to happen here but did not.
The altar, of carved wood in a semicircular form, dates from 1873, while the altarpiece depicting Christ on the cross was painted in 1773 by Alexander Kastman, later framed by a heraldic tent painting added in 1970. The altar rail and pulpit, also from 1773, are rococo work by the sculptor Jonas Berggren, decorated with gilded reliefs.
The church's organ has an interesting history of its own: an instrument built in 1955 was later moved elsewhere, and the current organ, built in 1973 by the German firm Gebrüder Jehnlich, was subsequently reworked by a Swedish organ builder in 2008.