The Scandinavian theatre of World War II encompasses the military and political events that took place between late 1939 and May 1945 in Scandinavia (including territories culturally associated with it, such as Finland, Greenland, Iceland, and the Faroe Islands), within the broader context of the European theatre of World War II.
Scandinavia was involved early in the events of the Second World War: in late November 1939, Finland was invaded by Soviet troops, intent on annexing strategic border areas, and signed the Moscow Peace Treaty, by which it had to cede about 10% of its territory after a conflict lasting just over three months. As a result, Finland aligned itself with Nazi Germany, and in June 1941 participated in the invasion of the USSR, opening a new front stretching from Lapland to the Gulf of Finland. Cooperation between Germans and Finns continued until September 1944, when the government in Helsinki capitulated in the face of renewed Soviet counteroffensives; Finnish and Soviet troops then cooperated in the Lapland War to expel the last German units from Lapland.
Denmark and Norway were invaded by Germany in April 1940 during the events of the so-called "Operation Weserübung": the Danes capitulated quickly, while the Norwegians resisted longer, also thanks to the support of an Anglo-French expeditionary force, but ultimately surrendered in early June 1940.
Denmark was initially treated leniently, subjected to Germany but still retaining some internal autonomy; however, growing opposition from institutions and the populace to the oppressive policies imposed by Germany led, in August 1943, to the dissolution of the government and full German military occupation. In Norway, the Germans installed a puppet state led by Vidkun Quisling, but due to his lack of support, the country was fully subjected to Germany, being established as a Reichskommissariat.
In both Norway and Denmark, various armed resistance groups formed in opposition to the German occupiers and local collaborators.
Sweden played an ambivalent role: the country, formally neutral and uninvolved in the conflict throughout its duration, on one hand supported Finland’s struggle against the USSR and maintained intense trade with Nazi Germany; on the other hand, particularly after 1943, it provided refuge and assistance to Danish and Norwegian resistance groups and the regular armed forces established by their respective governments-in-exile, as well as supporting the populations of occupied countries with humanitarian interventions.
Background
Scandinavia, geographically comprising Sweden, Norway, and Finland, was united by strong historical ties with Denmark (which, except for Greenland, is part of continental Europe). Together with Sweden, Denmark controlled the Øresund strait, the gateway to the Baltic Sea, and was thus a key hub for Northern Europe’s economy, although the Germany built the Kiel Canal in 1895 and expanded it in 1914, allowing rapid passage between the North Sea and the Baltic.
Sweden was a major producer of iron ore (essential for Germany’s industrial, civilian, and military power policies), which was exported through the Norwegian port of Narvik and two Swedish ports, unusable year-round due to ice, while Narvik, thanks to the Gulf Stream, remained accessible.
At the outbreak of World War II, the British, on the initiative of Winston Churchill, planned to send three battleships to disrupt traffic between Swedish and German ports in what was to be Operation Catherine, but the plan was abandoned due to other priorities for materials needed to convert the ships and a shortage of skilled labor.
Soviet Union and Finland
Toward the end of 1939, the Soviet Union requested territorial adjustments from Finland to improve the defense of Leningrad. It proposed a 30-year lease of the Hanko Peninsula, which, together with positions on the Estonian coast at Paldiski, would block access to the Leningrad Bay for hostile ships; it also demanded the withdrawal of the border in Karelia to place Leningrad beyond the range of heavy artillery and control of Petsamo, Finland’s only port on the White Sea and a potential threat to the Soviet port of Murmansk.
In exchange, the Soviet government offered some border areas. However, as Finland refused, the USSR opted for a violent resolution of the dispute; this casus belli was deemed pretextual by world public opinion, which sided with the Scandinavian country. At the time operations began (30 November 1939), World War II had already started three months earlier with the German invasion of Poland and the subsequent declarations of war by France and the United Kingdom against Germany. By late 1939, the forces of the two sides faced each other along the fortified Maginot Line and Siegfried Line in what was called the “Phoney War” due to its static nature and lack of fighting, while the Soviet Union had annexed the Baltic republics of Estonia, Latvia, and Lithuania through a forcibly imposed treaty.
Attention thus focused on the so-called Winter War: aid and volunteers willing to fight for Finland arrived from around the world, without distinction between democratic countries and those under totalitarian regimes, such as fascist Italy and the Kingdom of Hungary, with a significant presence of Scandinavians. The volunteers numbered 11,500, including 8,275 Swedes, 725 Norwegians, 800 Danes, 400 Hungarians, and 300 Americans of Finnish origin. The state that provided the most material aid to Finland was France: 145 aircraft, 500 artillery pieces, 5,000 machine guns, 200,000 grenades, 400,000 rifles, and twenty million rounds of ammunition.
German blitzkrieg
With the invasion of Norway, the Germans aimed to prevent what had been the main problem for their navy during the First World War, namely the imposition of a naval blockade line from Scotland to Bergen by the Royal Navy, made possible by Norway’s pro-British foreign policy. The possibility of a German attack on Norway had been theorized as early as 1929 in the book La strategia navale della prima guerra mondiale by German Admiral Wegener. However, in 1939, Hitler had told Admiral Erich Raeder, commander of the Kriegsmarine, that the war would not begin before 1944, and the German naval construction program was planned accordingly. The Bismarck-class battleships were not yet in service, and the German fleet was unable to confront the British fleet in open waters.
Nevertheless, Norwegian bases would be more useful than German ones for the U-boats, and Raeder, in October and December 1939, urged Hitler to plan the occupation of Norway, meeting initial resistance. Nazi theorist Alfred Rosenberg introduced his Norwegian protégé Vidkun Quisling to Raeder, who provided Hitler with new arguments for the invasion, but despite the OKW having already prepared the necessary plans, it was only the Altmark incident that finally led to the decision to undertake Operation Weserübung.
The Allies, through Churchill, also anticipated a German attack in the north, so much so that in a note dated 16 December 1939, he advocated “a major offensive war,” which would likely have prompted the Germans to invade Scandinavia; later, he stated: “We have more to gain than to lose from a German attack on Norway and Sweden.” The French prime minister, Édouard Daladier, expected to use the Altmark incident as a pretext to immediately occupy Norwegian ports “[...] with a sudden attack; it will be all the easier to justify this move in the eyes of public opinion the faster it is completed and the more our propaganda can exploit the memory of Norway’s recent complicity in the incident.”
On the other hand, the Winter War between the Soviet Union and Finland was already underway in the region, with both the Germans and the Allies as secondary players. At that time, the Germans were bound to the Soviets by the Molotov–Ribbentrop Pact, and they ensured strict neutrality and control over arms supplies to the Finns, despite having supported the growth of their armed forces in the past. The Allies, meanwhile, were attempting to deliver weapons and aid to the Finns through an expeditionary force that was nominally composed of “volunteers.” The Norwegian campaign of 1940 placed Denmark and Norway in the hands of the Reich, and these countries remained occupied until Germany’s surrender in 1945.
The Danish armed forces were utterly inadequate to defend the country, which was also vulnerable due to its flat terrain and lack of natural obstacles. The few army and navy aircraft were outdated and suited only for reconnaissance tasks; the navy, with 4,300 personnel, equipped only with a coastal defense ship with 150 mm guns, six torpedo boats, and seven submarines, (Excerpts from the Parliamentary Commission proceedings, Vol. 1, p. 177.) was in no way capable of stopping the German squadron that arrived in Copenhagen on 9 April 1940. The Danish naval air force, with its eleven seaplanes in Copenhagen, two others with the naval squadron in Aarhus, two more in Slipshavn, and nine land-based aircraft at the Avnø naval base, was supposed to oppose the hundreds of aircraft deployed by the Luftwaffe.
The two German infantry divisions assigned to the operation encountered only weak and symbolic resistance, also because the Danish government had not declared general mobilization. The ships of the Maersk Line, then A.P. Møller-Mærsk Gruppen, were placed under the management of the company’s New York office, and under Special Standing Order One, no order from Denmark could be accepted unless countersigned by the New York office led by Arnold Mærsk Mc-Kinney Møller. Ships outside Danish waters were placed under Allied control; some were sunk by German submarines during the conflict, such as the Leise Maersk, sunk on 23 November 1940.
Denmark formally remained under its own sovereignty, with its elected parliament and King Christian X of Denmark on the throne. However, Iceland was occupied by the British in the Operation Fork, which slightly preceded the similar German Operation Ikarus. The British occupation force was replaced by an American one in 1941. Subsequently, Iceland broke away from the personal union that tied it to Denmark with a vote by the Althing; on 9 April 1941, the Danish ambassador Henrik Kauffmann signed, without government authorization, an agreement with the United States authorizing the presence of American troops in Greenland, making it de facto American.
In Norway, in addition to the collaborationist government of Quisling, the Germans appointed a Reichskommissar in the person of Josef Terboven, while the occupation forces, initially consisting of a few tens of thousands of soldiers, later increased to 350,000 by 1945 following British attacks and commando raids (e.g., operations Claymore, Anklet, Gauntlet, as well as the subsequent Fritham and Musketoon). In German plans, Norway was intended to serve as a base for air and naval operations to prevent the Kriegsmarine from being bottled up in the Baltic and North Sea, as well as an excellent starting point for long-range reconnaissance aircraft like the Focke-Wulf Fw 200.
Norway
Norwegian armed forces in exile
While the Allies focused their operations in the far north and the Germans strengthened their positions, various degrees of resistance to the occupiers emerged in the occupied countries. The Norwegians actively collaborated with the SOE (Special Operations Executive, the British special operations service), providing local contacts, intelligence, and personnel ready to infiltrate under the auspices of the Norwegian government-in-exile; ground, air, and naval forces were also established in British territory.