The Swedes had to take up arms to defend the border numerous times during the Middle Ages and the 16th century, especially after the Muscovites took over Novgorod in the 1470s. These conflicts did not end until 1323, with the peace treaty of Pähkinäsaari, which finally established that Finland was part of the kingdom of Sweden. Meanwhile, the people of Novgorod made repeated raids into Finnish territory, burning the city of Turku in southwestern Finland as late as 1318. The Swedes arranged two more crusades, one in 1239, to Häme in central Finland, and another in 1293, to Karelia (Viborg) in the East. Finland was a country rich in natural resources in the middle and came to be seen as a desirable territory by both sides from about the twelfth century onwards.

To the east of Finland lay the Novgorod republic, which was Greek-Orthodox. The first crusade was also part of much wider political and ecclesiastical perspective. Archaeological finds have shown that Christianity had reached the Finns as early as the eleventh century, and the main purpose of the crusade was thus to establish Swedish dominion in Finland and organize a bishopric there. The chronicle’s claim that the Bishop ‘baptized’ the Finns has later been modified.

In Finnish history, the prehistoric era is generally considered to end and the Middle Ages to begin in the 1150s, when, according to a Swedish chronicle, King Erik of Sweden and English-born Bishop Henry undertook a crusade to the southwestern parts of Finland.

Medieval castles