The Protestant Reformation reached Finland in the early 16th century as part of Sweden, which then ruled the region. Initiated by Martin Luther’s ideas, the Reformation took hold in Sweden under King Gustav Vasa, who broke ties with the Catholic Church in the 1520s. As Sweden embraced Lutheranism, Finland, as part of the kingdom, followed suit.
Finland’s shift to Lutheranism was primarily driven by Swedish authorities and church reforms. The Catholic Church's properties were confiscated, monasteries were closed, and Catholic clergy were replaced by Lutheran priests. Mikael Agricola, a Finnish bishop and key figure in the Reformation, played a central role in establishing Lutheranism in Finland. He translated the New Testament into Finnish in 1548, promoting literacy and making religious texts accessible to the common people.
By the mid-16th century, Finland had officially become Lutheran, with the Lutheran Church becoming a central institution in Finnish society. The Protestant Reformation marked a significant shift in Finland’s religious landscape, aligning it with the rest of Sweden and Northern Europe in its embrace of Lutheranism.