Mikael Agricola
One of the most important historical figures in Finland you should know is Mikael Agricola. Mikael Agricola (c. 1510 – 9 April 1557) was a Finnish Lutheran preacher who was a leading proponent of the Protestant Reformation in Sweden, including Finland, which was a Swedish possession at the time. He is known as the "Father of Literary Finnish."
Agricola was consecrated as bishop of Turku without papal authority in 1554. He maintained the Lutheran reform of the Finnish church (then a member of the Church of Sweden). He translated the Fledgling Testament into Finnish and wrote the prayer book and hymns that were used in Finland's new Lutheran Church. This work established the orthography norms that serve as the foundation for modern Finnish spelling. His meticulous craftsmanship is very impressive.
Agricola led a party on a diplomatic journey to Russia in 1557, and he remained in Moscow from 21 February to 24 March negotiating a peace deal, the Treaty of Novgorod (1557). On April 9, he became unwell and died on the Kyrönniemi peninsula, near the town of Uusikirkko (now Polyane) on the Karelian Isthmus. This is also Elias Lönnrot's birthday, and it is observed throughout Finland as Finnish Language Day. Agricola was most likely buried inside Viipuri's church, but the precise location of his grave is unknown.