In the 13th century Sweden became interested in the area inhabited by the
Karelians.
The Swedish started to build the castle of Vyborg 1293 during the third crusade to secure
the eastern border of their conquest. The Swedish administrative system was spread to the
territory; the County of the castle of Vyborg was formed to be its foundation and it
supervised the tax collection, the legal proceedings and the mission work by the Catholic
church.
The border between Russia and Sweden, later between Russia and Finland, has divided the
Karelians since 1323.
