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
Postage stamps and postal history of Latvia Postal Service routes in Finland. In 1685 the Duke of Courland Friedrich Casimir initiated his own postal service and asked the Swedish authorities to cease their postal operations within his territory, but King Charles XI of Sweden ignored his request and stood for his rights in Courland. On 5 July 1710, Russian troops under the command of Tsar Peter I of Russia took over Riga and made it a part of the Russian Empire. During World War I, Latvia was occupied by Germany, and used German stamps overprinted by the Ober Ost. In 1919, German stamps were handstamped "LIBAU", but