On this day in 1913, a peace treaty is signed ending the First Balkan War, in which the newly aligned Slavic nations of Serbia, Montenegro, Bulgaria and Greece had driven Turkish forces out of Macedonia, a territory of the Ottoman Empire located in the tumultuous Balkans region of southeastern Europe.
After rebellion in Macedonia—led by a secret society of nationalists known as the Young Turks—shook the stability of the sultan's hold on Ottoman territory in Europe in 1908, the Austro-Hungarian empire acted quickly to annex the dual Balkan provinces of Bosnia-Herzegovina and to encourage Bulgaria, also under Turkish rule, to proclaim its independence. Austria-Hungary's actions clearly upset the delicate balance of power in the Balkans. The small, boisterous monarchy of Serbia was outraged by the annexation, having long regarded Bosnia-Herzegovina as part of its own rightful territory due to their shared South Slavic heritage. Meanwhile, czarist Russia—an important supporter of Serbia and the other great European power with influence in the Balkans region—felt its own interests threatened by its rival's actions.
In the spring of 1912, Serbia, Bulgaria, Montenegro and Greece, encouraged by Russia, aligned with the objective of taking control of some or all of the lands still occupied by the Ottoman Empire in Europe. Though the disparate Balkan peoples nursed intense hatreds of one another, they were compelled to join forces and act quickly in order to strike at Turkey—now ensnared in a war with Italy over territory in Libya—in its weakness. On October 8, 1912, Montenegro declared war on Turkey; Serbia, Bulgaria, and Greece followed suit on October 17.
Surprisingly, the Ottoman army was quickly and decisively defeated, as the Balkan forces drove the Turks from almost all of their territory in southeastern Europe over the course of a month. The great powers of Europe—Britain, France, Germany, Austria-Hungary and Russia—scrambled to exert control over the region in the wake of Turkey's withdrawal, and a congress was convened with representatives of the belligerent nations in London in December 1912 to draw up post-war boundaries in the Balkans. Over the course of the next several months and 63 meetings, as well as renewed hostilities on the battlefield, an agreement was reached, and Macedonia was partitioned between the victors of the First Balkan War. Nevertheless, the peace concluded May 30, 1913, was only tenuous, as Bulgaria felt cheated out of its rightful share by Serbia and Greece.
By 1913, many in both Austria-Hungary and Germany—especially within the countries' military leadership—had decided that a preventive war against Serbia would be necessary to restore the empire's prestige and power; as Russia was almost certain to back Serbia in any such conflict, a third war in the Balkans would most likely proceed directly to a general European one, with Germany and Austria-Hungary facing off against Serbia, Russia, Russia's primary ally, France, and possibly Britain. For the time being, however, both Kaiser Wilhelm, emperor of Germany, and Archduke Franz Ferdinand, heir to the Austrian throne, continued to see the possibility of a peaceful resolution of the Balkans question, though they disputed the means of achieving it. Franz Ferdinand's assassination, by a Serbian nationalist, in Sarajevo on June 28, 1914, however, put an end to any such negotiations and toppled Europe, already teeming with unresolved conflict and irreconcilable differences between the great powers, headlong into the First World War.
Taken from: http://www.history.com/this-day-in-history/the-first-balkan-war-ends [30.05.2013]