Operation Weserübung's effects on Sweden became strategically encircled by the German-Soviet pact. Since the Baltic states; Estonia, Latvia, and Lithuania; had been forced to accept "limited" Soviet forces on their soil, in the autumn of 1939, they were de facto more or less in a state of occupation. For Sweden and Finland, this meant that the only possible trade route to nations other than Germany and the Soviet Union, was through Petsamo harbour, in the far north of Finland. This seriously hampered the supply situation in both these nations. It also meant that an invasion of Sweden could be launched from almost any direction. Sweden
Finland–Russia border most of which were Savonians. After the Finnish War, the Treaty of Fredrikshamn converted all of Finland from Swedish territory to a Russian possession, the Grand Duchy of Finland. The Finnish–Russian border was moved back to the pre-1721 location, so that the Grand Duchy gained the so-called "Old Finland", territories previously held by Sweden, in 1812. After Finland became independent in 1917, there was the Finnish Civil War in 1918, and even after this war, the Russian Civil War continued. Finnish activists often crossed the border into Soviet territory in order to fight in the "heimosodat", wars aiming at Finnish