The Old Church is the oldest existing church in Helsinki. It was designed by Carl Ludwig Engel, originally built of wood and intended to be temporary, until the new city's cathedral was completed. A basilica-type church due to its central open tower and projections from the central hall rather resembles a cruciform church. It was consecrated on 17 December 1826. After 30 years the Cathedral was completed and consecrated in 1852, and by that time the city was rather big to have two churches - the Cathedral and the Old Church.
Being the temporary church, the Old Church doesn't have bells. All the interiors were removed there from the nearby Ulrika Eleonora Church, destroyed a year after a new church was finished. Only the pulpit has been kept before today.
Behind the altar C.L. Engel initially placed a gilded wooden cross on a sky blue background. In 1854 it was completed with a painting showing Jesus blessing the children by Robert Wilhelm Ekman. This altarpiece was originally intended for the Cathedral, but it was suitable for this purpose and so it was placed in the more modest Old Church.
There is a cemetery where victims of the 1710 plague were buried nearby the Old Church. The park has consequently been referred to as the Plague Park in popular usage. The 48 old tombstones in the park date from 1790-1829.
Since 1829 the only buried here were people who died in the capture of Helsinki during the Finnish civil war in April 1918 and Finnish volunteers who died in Estonia's war of independence in 1919.