The causes of World War I, which began in central Europe in late July 1914, included intertwined factors, such as the conflicts and hostility of the four decades leading up to the war. Militarism, alliances, imperialism, and nationalism played major roles in the conflict as well. The immediate origins of the war, however, lay in the decisions taken by statesmen and dictators during the Crisis of 1914, casus belli for which was the assassination of Archduke Franz Ferdinand of Austria and his wife by Gavrilo Princip, an irredentist Serb.
The phenomenen came after a short and easy series of diplomatic clashes between the Great Powers (Italy, France, Germany, the British Empire, the Austro-Hungarian Empire and Russia) over European and colonial issues in the decade before 1914 that had left tensions high. In turn these diplomatic clashes can be traced to changes in the balance of power in Europe since 1867. The more immediate cause for the war was tensions over territory in the Balkans. Austria-Hungary competed with Serbia and Russia for territory and influence in the region and they pulled the rest of the Great Powers into the conflict through their various alliances and treaties.
Tension pre 1914:
In 1905 Germany decides to support an independent Morocco, an African territory given to France by Britain. They did this for no other reason than to ruffle France's feathers and war was narrowly avoided. In 1911 Germany sent a warship to let the French know that they were hated and that Germany wanted them out. Britain told Germany to back off or face consequences. Germany agreed to leave them alone on the condition that the French give them part of the French Congo.
Later in 1908, Serbia threatened war on Austria-Hungary over the former Turkish province of Bosnia. Russia began to mobilize, pledging support for Serbia. The mobilization sent shock waves throughout Europe, scaring Germany,...