The attack by Hitler’s Germany on Norway followed the logic of the war, yet for most of the country’s residents it came as a complete surprise.
Norway declared its neutrality in 1905, immediately after leaving its union with Sweden and gaining full independence. Oslo kept to that course during World War I despite pressure from Britain and the actions of German submarines, which sank nearly half of the merchant ships sailing under the Norwegian flag.
At the start of World War II, both London and Berlin again tried to draw the Scandinavian country into the conflict, though they used different methods. British authorities sought, through diplomatic channels, to obtain from King Haakon’s government the use of vessels from Norway’s merchant fleet. Germany, for its part, began sinking British ships in Norwegian territorial waters.
For the Nazis, control of Norway’s coastline served several strategic aims at once. It meant not only access to the ice-free Arctic ports through which Swedish iron ore was shipped to the Third Reich, but also favorable positions for submarine attacks on Britain and on the sea lanes linking it with North America.
Norwegian fjords were equally important to London. Had the British established themselves there, as their plans envisioned, Germany would effectively have lost access to the North Sea and been confined to the Baltic. The situation in Scandinavia was further sharpened by the Winter War: after it began, Britain and France started viewing Norwegian territory as a convenient bridgehead for sending reinforcements to the Finnish army.