The Invasion of Norway by Nazi Germany during World War 2 led to a two-months campaign in which the Germans eventually prevailed.
Norway was strategically important because the iron ore from Sweden, transported by railway to the Norwegian port of Narvik, was feeding the German war machine. Another issue was that Norway, once occupied by the Germans, would have offered them naval bases at the Atlantic. Taking into account Norway's importance, the British and the French also had a contingency plan.
The Germans gave the code name Operation Weserübung to the invasion that also included Denmark.
The Norwegians had theoretically six infantry divisions, but most of the troops were not yet mobilized. The Norwegian Air Force and Navy were insignificant numerically, and their equipment was obsolete.
On April 9, 1940, at the beginning of Operation Weserübung, the German paratroopers captured airfields near Oslo, Kristiansand, and Stavanger. The Norwegians, with a few notable exceptions, were taken by surprise, and the Germans occupied the first objectives without major problems.
The German warships landed thousands of infantrymen in a few important Norwegian ports. The German heavy cruiser Blücher was sunk by coastal batteries when entered the Oslo fjord leading a troop convoy, which was the biggest Norwegian success in the first part of the campaign.
The conquest of ports and airfields allowed the Germans to bring reinforcements and supplies, as well as using the Norwegian airfields.
By Jniemenmaa [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/deed.en) ], via Wikimedia Commons
Bundesarchiv, Bild 101II-MW-5607-32 [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0/de/deed.en)], via Wikimedia Commons
Although initially withdrew due to the surprise, the Norwegians gradually began to oppose more resistance.
Shortly after the beginning of the German invasion, the British and the French decided to implement their intervention plan in Norway.
The British had a far superior naval force in numbers, tonnage, and experience, compared to the Germans.
The Kriegsmarine sought to avoid a decisive battle with the Royal Navy, and the more random naval encounters between the two navies led to approximately equal losses, but the losses felt more for the Germans because their navy had few ships.
Starting with April 14, the Allies landed troops in central and northern Norway, in ports unoccupied by the Germans. Although they managed to delay the German advance, the Allies were forced to retreat from central Norway, in front of the German superiority in aircraft and heavy weapons.
Instead, the Allies had numerical superiority in the north of Norway. On May 27, the French Foreign Legion infantry, supported by light tanks, together with Norwegian troops, captured Narvik. Only that in the meantime, the Germans had launched the offensive over France, the situation becoming critical after the breakthrough at Sedan. Preparing the evacuation from Dunkirk, the Allies decided withdrawal from Norway.
The Norwegian Army, without the Allied support, ceased to fight, and Norway remained occupied by the Germans until the end of World War 2 in Europe.