Olavinlinna (Swedish: "Olofsborg") or St. Olaf's Castle is a 15th century castle located on a rocky island between the lakes Haapavesi and Pihlajavesi connected to the Bay of Lake Saimaa in northern Finland in Savonlinna Provincial Cham.
|Attribution: Miraceti, License|
Construction of the castle was begun in 1475 by the Danish Knight Erik Axelsson Tott, who had engaged in strengthening the Vyborg Castle. Erik Axelsson Tott decided that the powerful fortification should be build to protect the strategically important Savo region. The castle was supposed to repel Russian attacks from the east and to guarantee the control of the Savo region for the Swedish Crown. Initially, the castle was named Nyslott (Swedish: New Castle), then it was named Olavinlinna, Castle of St. Olaf, in honor of the Catholic saint of the 11th century, especially in Scandinavia revered as the patron saint of the Knights.