The Finnish Orthodox Church is the second official state church of Finland, beside the Lutheran Church of Finland. Eastern Orthodox Christianity was introduced to Finland during Russian rule in the 19th century. In Helsinki, Viipuri and Karelian Isthmus, Orthodoxy was associated with the country's ruling elite, however many rural Finns, Saami and Karelians where also members of the Orthodox Church.
Shortly after Finland declared independence from Russia in 1917, the Finnish Orthodox Church declared its autonomy from the Russian Orthodox Church. In 1923, the Finnish Church completly separated from the Russian Church, becoming an autonomous part of the Orthodox Church of Constantinople. The Gregorian Calendar was also adopted. Other reforms introduced after independence include changing the language of high mass from Church Slavonic to Finnish and the transfer of the Archepiscopal seat from the Karelian and Russian speaking city of Viipuri to the Finnish speaking city of Sortavala.
Until World War II, majority of the Orthodox Christian in Finland were in Karelia. As a consequence of the war, many residents of that border province evacuated to other parts of the country. The monastery of Valamo was evacuated in 1940 and the monastery of New Valamo was founded in 1941 at Heinävesi. Later, the monks from Konevitsa and Petsamo monasteries also joined the New Valamo monastery. The nunnery of Lintula at Kivenapa (Karelian Isthmus) was also evacuated, and re-established at Heinävesi in 1946. A new parish network was established, and many new churches were built in the 1950s. After the city of Viipuri was lost to the Soviet Union, its Diocesan seat was moved to Helsinki. A third Diocese was established at Oulu in 1979.
To this day, Orthodoxy is practiced mostly by Russians, Karelians and the Sami (Koltta Tribe), although it has shed the image of the privileged class it was once associated with. The Orthodox Christian Church has about 60.000 members.