The Great War began on August 3rd 1914, but was triggered on June 28th, when a member of the Serbian militant group called the "Black Hand," Gavrilo Princep, assassinated Austrian archduke Frances Ferdinand and his wife. The assassination was a result of the nationalism caused by the molding of the Yugoslavian provinces into Serbia. The Serbian government, which had a vested interest in the downfall of the Austrian Empire, was implicated as being involved in the plot and quickly became the reason for war. Though Germany declared war on France on August 3rd, it is important to remember that Russia was the first to mobilize, considered an act of war. This was quickly followed by France, and finally Germany. Though Germany was the most prepared for this war, they did not want to hurt their industry and did not want to fight a two front war.
Austria, outraged with the assassination of the archduke, saw a chance to annex a critical portion of their new neighbor Serbia. The loosely held Empire was the last of its kind, and in danger of loosing its control. This was due to fierce nationalism in the Balkans, due to the occupation of Bosnia (Sarajevo). On July 13th, 1914, the Austrians made an ultimatum saying all Serbs must leave Albania. The Serbians were not willing to agree to a demand aimed at hurting their government, and immediately mobilized for war. On July 28th, three days after Yugoslavia refused to yield to their demands, the Austrians officially declared war. Austria's only hesitation came in Yugoslavia's defensive treaty with Russia, and for this Austria turned to Germany. Germany told Austria to begin the war, and if it evolved into a larger conflict they would support them. Clearly, Germany was not the instigator on this front.
The following day, on July 29th, Russia began mobilization with the intent of protecting Yugoslavia from Austria. Tsar Nicholas II ruled the Russian Empire as an absolute monarch until he was forced to accept a reduction in power and to implement a parliament called the State Duma due to growing political unrest.