It was originally fortified by Snare's castle but this was replaced in the 14th century by Kalundborg Friary, now in ruins, with its ring walls and ditches.

[2] As the church had fallen into a state of disrepair by the beginning of the 19th century, restoration work was carried out first from 1867 to 1871 under the leadership of architect Vilhelm Tvede (1826–1891) when the central tower was rebuilt.

The window arches as well as the pilasters and sunken columns inside the church suggest the involvement of Lombard builders from northern Italy.

[8] The other towers are also named after saints: St. Anne's to the east, St. Gertrude's to the west, St. Mary Magdalene's to the south and St. Catherine's to the north.

[9] The masonry, on the other hand, is comparable to that of other early brick buildings in the area such as St. Bendt's Church in Ringsted.

Little remains of the church's original furnishings apart from the granite font, sculpted by a mason who worked for the Esbern Snare family.

A mural fragment (c. 1225) in the north window of the chancel shows that the interior was once decorated with wall paintings or kalkmalerier.

The altarpiece was designed in 1650 by woodcarver Lorentz Jørgensen (c.1644–c.1681) of Holbæk while the pulpit (1871) is the work of Vilhelm Tvede.