Ethnic tensions made the region vulnerable to conflict.
Explanation:
The wars of the Balkans were two wars that occurred in southeastern Europe from 1912 to 1913. The first one faced the Ottoman Empire with the so-called Balkan League formed by Bulgaria, Montenegro, Greece and Serbia. The small Balkan nations managed to expel the Ottomans from almost all the territory of the peninsula, but they could not avoid confronting each other over the distribution of the lands that had been taken from them, which led to the Second Balkan War. Bucharest put an end to the wars, but left the area in an unstable balance, due to the desire of the defeated Bulgarians to take revenge as soon as the opportunity arose The contests did not satisfy the appetites of the Greek and Serbian nationalists, who remained eager to expand their States at the expense of Ottomans and Austro-Hungarians, respectively.
