You need to specify which war- Europe has had a lot of them.
the assasination of Archduke Franz fernidand
The immediate cause was the breaking away of eleven southern states from the union, electing their own President.
The Germans had been slowly building up their military after the fall of the Weimar Republic; their invasion of Poland in 1939 was probably the most immediate cause of the world war.
In Europe it was the attack of Poland by the German Nazis on 9-1-39. In the Pacific it was the attack on the US Naval Fleet at Pearl Harbor, Hawaii by the Japanese on 12-7-41 that was the immediate cause of World War 2 for the USA.
The spread of Communisim
The Thornton Affair.
Well, the immediate cause of secession deals with slaves and the rights of the civil war. Figure the rest out, because I can't
World War I had 4 long-term causes and one immediate cause. The assassination of the Austro-Hungarian archduke was the immediate cause, the reason war was justified enough to actually begin. The other four are the MAIN causes of the war, Miliatariam, Alliances, Imperialism and Nationalism.
The immediate cause of the first revolution in March 1917 was the disastrous impact of the First World War.
Archduke Franz Ferdinand of Austria.
The German invasion of Poland in 1939.