The church was originally designed in the late 15th century by an unknown “Espoo master” and built between 1485 and 1490 under his supervision. The only remaining parts of the medieval church are the eastern and western parts of the nave. The weapons room was removed between 1804 and 1806 and certain other parts of the church, including the original sacristy, were taken apart between 1821 and 1823 when the building was converted into a more spacious cruciform church.
The vaults and walls of the older parts of the cathedral are decorated with murals, largely painted in the 1510s, that depict both biblical scenes and events in the daily life of the people. The paintings were covered in the 18th century as they were thought to be “crude and superstitious” but uncovered again and conserved during renovations in 1931. The current campanile of the cathedral was completed in 1767 and its top part was redone between 1868 and 1869.( Wikipedia)