As the Ottoman Empire weakened in the Nineteenth Century, the long-submerged Balkan nations began to reappear, though their independence was compromised as they became pawns for competing European powers.
But by about the turn of the century, the local kingdoms began to assert themselves; most importantly, from 1903 Serbia became increasingly defiant of its former protector Austria-Hungary.
When the Young Turks seized power in Constantinople in 1908, Austria took advantage of the confusion and annexed Bosnia, hoping to get a firmer grip on the Balkans.
Instead, the annexation brought on a grave European crisis and provoked Serbian nationalists into launching a terror campaign against Austria that further destabilized the area.
In early 1912, Russia tried to form a Balkan alliance against Austria, but the Balkan states had other ideas: they redirected the alliance against the Ottoman Empire, launched the First Balkan War in October, and within a few months had almost completely driven the Turks out of Europe.
The victors soon squabbled over how to carve up the conquests. During the summer of 1913 disgruntled Bulgaria attacked its former allies in the Second Balkan War - and was promptly trounced.