There is no straight or clear line between the formation of the two alliance blocks and the outbreak of war in the summer of 1914. For simplicity’s sake, four factors can be emphasized to set the stage for the July Crisis following the Serbian assassination of the Austrian Archduke in Sarajevo. 1) A series of confrontations—all peacefully resolved—between Germany and the Entente powers created an atmosphere of distrust and belligerence. 2) Following from the first, European powers all chose to dramatically expand their military readiness both in terms of monetary resources and available troops. Armies of tens of thousands became armies of hundreds of thousands or even millions. 3) Battle plans were formulated in the high levels of the military establishments throughout Europe. This is particularly true of Germany, since it faced the daunting prospect of fighting the combined power of England, France, and Russia on two fronts. 4) Finally, an aura of inevitability that war would come grew throughout Europe and especially in Germany. War between the blocks increasingly came to be seen as probable or even inevitable, again feeding into the increasing tensions. In Germany, in particular, it was thought that if war were to come, the earlier it came the better because Russia had embarked on massive military rebuilding after the disastrous Russo-Japanese War. German fears of Russia were in a state of continuous escalation in the run-up to WWI.

It is too much to get into the precise chain of events that led from Franz Ferdinand’s assassination at the hand of Serbian nationalists to the outbreak of the war. The short version of the story is that the act brought the Kingdom of Serbia into direct tension with Austria-Hungary. Diplomatic conflict rose during July of 1914 and end with a breaking of relations between Serbia and Austria. The major European powers moved in the background of this latest Balkan crisis, each expecting the other of readying for a preemptive strike. Within days of each other, Russia, Germany and France called for general mobilization of their armies, the first decisive step toward full-scale war. Military strategies, long ready, were put in place. Between July 30 and August 6, all major European powers (including the Ottoman Empire) declared their involvement in the conflict.