Belligerents:

Serbia, Greece, Montenegro, Roumania.
Bulgaria.
Turkey.

Cause:

In February 1912 a treaty was concluded between Bulgaria and Serbia, whereby it was agreed that North-west Macedonia should go to Serbia, another part to Bulgaria, and the zone lying between these two should be submitted to the arbitration of the Czar. In December 1912, in the First Balkan War, Austria protested against the occupation by Serbia of Durazzo on the Adriatic, and of Scutari by Montenegro. Serbia declared that Bulgaria did not adequately support her in resisting the Austrian demand, felt impelled to claim more territory in Macedonia, and refused to carry out the provisions of the treaty with Bulgaria. Serbia was ready to arbitrate. Russia was inclined to support the Serbian claim. Bulgaria hesitated.

Occasion:

While the dispute was still in the balance the aggressive party in Bulgaria got the upper hand, and war was declared against Serbia and Greece in June 24, 1913, only a few months after the cessation of hostilities in the First Balkan War.

Course of the War:

The Bulgarians found themselves invaded on four frontiers. While they were being driven back by Serbia and Greece, the Turks repudiated the Treaty of London and retook Adrianople, and Roumania advanced from the north and without striking a blow annexed a large slice of territory in the Dobrudja. Bulgaria was obliged to yield.

Political Result:

By the Treaty of Bukarest, August 10, 1913, Serbia acquired a large district of South-east Macedonia, Greece obtained Kavalla, and Roumania was given possession of the territory her troops had occupied.

By the Treaty of Constantinople, August 1913, Bulgaria ceded back to Turkey more than half of the territory won in the previous war, including Adrianople.

Remarks:

Bulgaria being again restricted in territory felt she had been betrayed by the Powers, who did nothing to enforce the engagements of the Treaty of London. Her rivals, Serbia and Greece, gained at her expense. On the other hand, Bulgarian responsibility for the outbreak of the second war was undoubted.

The European Powers, by acting together, prevented the Balkan conflict from spreading into a European War. But the Treaty of Bukarest was no settlement, and was a signal exposure of their inability to solve the Balkan problem, which was destined to be the spark for a world-wide conflagration.