Why did war break out in Europe in September 1939?

Essay from the year 2002 in the subject History Europe - Germany - National Socialism, World War II, grade: 1C, University of Stirling, course: Modern European History, 1919 - 1991, language: English, abstract: War broke out in Europe in September 1939 because of the conjunction of several factors. However, the over-riding factor was the fruition of Hitler's dynamic ideological foreign policy aims to create lebensraum and racial mastery. Although Hitler's aims did not run to a strict timetable this does not mean that they were unimportant, or that there was no associated plan and that he was therefore a mere opportunist. After all, the strength of any plan lies, not in its rigidity, but in its flexibility to adapt to beneficial developments as they arise. To be able so to do the German domestic, economic and military infrastructure had to be in place - such was Hitler's plan. In addition, the breakdown of the European diplomatic order in the face of new, dynamic ideologies and the manipulation of the international system by Hitler clouded his true intentions. Britain and France's foreign policies also contributed to initially delaying the onset of war, as did the dilatory foreign policy of Soviet Russia. A change of attitude towards Germany from the western democracies and the increase in pace of German expansionism, together with a policy change to an alliance with the Soviet Union, would herald the outbreak of eventual war in September 1939.