Fact File : Declaration of War on Finland, Hungary and Romania
5 December 1941
Location: Finland, Hungary and Romania
Churchill, Hitler, Stalin, Finnish Prime Minister Rangell, General Horthy (Hungarian dictator), Antonescu (Romanian ruler).
Outcome: Britain at war with Finland, Hungary and Romania.
Colonel General Von Falkenhorst, right, and Field Marshal Baron Mannerheim review Finland's armed forces©
Finland's part in the war began when the Soviet Union attacked the Karelian isthmus in November 1939, in what was called the Winter War. Despite a vigorous counter-attack, civilian casualties were too high for Finland and a treaty was signed on 12 March 1940 agreeing to Stalin's demands. Britain and France had considered providing the Finns with military assistance, but they were too late.
Influenced by the Winter War, Finland joined forces with Nazi Germany against the Soviet Union. Germany provided Finland with military equipment because Hitler saw the strategic advantage of the Finns' co-operation in an attack on the Soviet Union. From 25 June to 6 July 1940, the Finns fought the largest military battle in Nordic history alongside the Germans, regaining much of the territory they had lost during the Winter War.
Romania and Hungary joined the Tri-partite Pact - originally signed by Germany, Japan and Italy - in November 1940, as Hitler prepared his attack against Bolshevism on the Eastern Front.
Hungary became essential in the defence of the Reich's outworks. Good soldiers, the Hungarians were nonetheless pitted against the daunting Red Army and the Hungarian dictator General Horthy considered defection until Hitler kidnapped his son.
Romania also played a vital role in the German war effort. After a German-Romanian economic agreement in 1939, German companies came to control much of the Romanian economy. By 1941, German-owned companies produced nearly half of Romania's crude oil output, and the German war effort relied heavily on Romanian oil.
Britain declared war on Finland, Hungary and Romania on 5 December 1941, following the signing of the Tri-partite Pact and Finland's alliance with Germany.
However, all three of these countries were to change their allegiance before the end of the war. By March 1944, the Romanian ruler Antonescu made contact with the Western Allies, and Romania declared war on Germany on 24 August that year. Hungary started negotiations with the Allies in early 1944, and was occupied by German forces in March 1944; and Finland went contrary to German wishes and made peace with the Soviet Union on 19 September 1944.
The fact files in this timeline were commissioned by the BBC in June 2003 and September 2005. Find out more about the authors who wrote them.