Norwegian campaign in the context of "Plan R 4"

At the outbreak of World War II, Charles de Gaulle was put in charge of the French 5th Army's tanks (five scattered battalions, largely equipped with R35 light tanks) in Alsace, and on 12 September 1939, he attacked at Bitche, simultaneously with the Saar Offensive.

In late February 1940, Paul Reynaud told de Gaulle that he had been earmarked for command of an armoured division as soon as one became available. In late March, de Gaulle was told by Reynaud that he would be given command of the 4th Armoured Division by 15 May. The government appeared likely to be restructured, as Édouard Daladier and Maurice Gamelin were under attack in the aftermath of the Allied defeat in Norway, and had this happened de Gaulle, who on 3 May, was still lobbying Reynaud for a restructuring of the control of the war, might well have joined the government. By 7 May, he was assembling the staff of his new division.

The Norway Debate, sometimes called the Narvik Debate, was a momentous debate in the British House of Commons from 7 to 9 May 1940, during the Second World War. The official title of the debate, as held in the Hansard parliamentary archive, is Conduct of the War. The debate was initiated by an adjournment motion enabling the Commons to freely discuss the progress of the Norwegian campaign. The debate quickly brought to a head widespread dissatisfaction with the conduct of the war by Neville Chamberlain's government.

At the end of the second day, there was a division of the House for the members to hold a no confidence motion. The vote was won by the government but by a drastically reduced majority. That led on 10 May to Chamberlain resigning as prime minister and the replacement of his war ministry by a broadly based coalition government, which, under Winston Churchill, governed the United Kingdom until after the end of the war in Europe in May 1945.

The German invasion of Denmark (German: Operation Weserübung – Süd), was the German attack on Denmark on 9 April 1940, during the Second World War. The attack was a prelude to the invasion of Norway (German: Weserübung Nord, 9 April – 10 June 1940).

Denmark's strategic importance for Germany was limited. The invasion's primary purpose was to use Denmark as a staging ground for operations against Norway, and to secure supply lines to the forces about to be deployed there. An extensive network of radar systems was built in Denmark to detect British bombers bound for Germany.

The Battles of Narvik were fought from 9 April to 8 June 1940, as a naval battle in Ofotfjord and as a land battle in the mountains surrounding the north Norwegian town of Narvik, as part of the Norwegian campaign of the Second World War.

The two naval battles in Ofotfjord on 10 April and 13 April were fought between the British Royal Navy together with the Polish Navy (under British supreme command) and the German Kriegsmarine, while the two-month land campaign was fought by Norwegian, French, British, and Polish troops against German mountain troops, shipwrecked Kriegsmarine sailors, and German paratroopers (Fallschirmjäger) from the 7th Air Division. Although defeated at sea off Narvik, losing control of the town of Narvik and being pushed back towards the Swedish border, the Germans eventually prevailed because of the Allied evacuation from Norway in June 1940 following the Battle of France.

World War II or the Second World War (1 September 1939 – 2 September 1945) was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many nations mobilising their resources in pursuit of total war. Tanks and aircraft played major roles, enabling the strategic bombing of cities and delivery of the first and only nuclear weapons ever used in war. World War II is the deadliest conflict in history, causing the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were put on trial for war crimes.

The causes of World War II included unresolved tensions in the aftermath of World War I, the rise of fascism in Europe and militarism in Japan. Key events preceding the war included Japan's invasion of Manchuria in 1931, the Spanish Civil War, the outbreak of the Second Sino-Japanese War in 1937, and Germany's annexations of Austria and the Sudetenland. World War II is generally considered to have begun on 1 September 1939, when Nazi Germany, under Adolf Hitler, invaded Poland, after which the United Kingdom and France declared war on Germany. Poland was also invaded by the Soviet Union in mid-September, and was partitioned between Germany and the Soviet Union under the Molotov–Ribbentrop Pact. In 1940, the Soviet Union annexed the Baltic states and parts of Finland and Romania, while Germany conquered Norway, Belgium, Luxembourg and the Netherlands. After the fall of France in June 1940, the war continued mainly between Germany, now assisted by Fascist Italy, and the British Empire, with fighting in the Balkans, Mediterranean, and Middle East, East Africa, the aerial Battle of Britain and the Blitz, and the naval Battle of the Atlantic. By mid-1941 Yugoslavia and Greece had also been defeated by Axis countries. In June 1941, Germany invaded the Soviet Union, opening the Eastern Front and initially making large territorial gains along with Axis allies.