The war between the Allies was fought over the possession of this triangle. The larger portion of it had in the war against Turkey been occupied by the forces of Servia; and the nation, inflamed by the military spirit of the army, had made up its mind that, treaty or no treaty, it should not be evacuated. On the south, especially above Vodena, the Greeks had occupied a section of the fatal triangle. And the two governments had decided that they would not tolerate the driving of a Bulgarian wedge between New Servia and New Greece. Bulgaria, on the other hand, was inexorable in her demands on Servia for the fulfilment of the terms of the Treaty of Partition. At the same time she worried the Greek government about the future of Saloniki, and that at a time when the Greek people were criticizing Mr. Venizelos for having allowed the Bulgarians to occupy regions in Macedonia and Thrace inhabited by Greeks, notably Seres, Drama, and Kavala, and the adjacent country between the Struma and the Mesta. These were additional causes of dissension between the Allies. But the primary disruptive force was the attraction, the incompatible attraction, exerted on them all by that central Macedonian triangle whose apex rested on the ruins of Czar Samuel’s palace at Ochrida and whose base extended from Saloniki to Golema Vreh.
From that base line to the Black Sea nearly all European Turkey (with the exception of the Chalcidician Peninsula, including Saloniki and its hinterland) had been occupied by the military forces of Bulgaria. Why then was Bulgaria so insistent on getting beyond that base line, crossing the Vardar, and possessing herself of Central Macedonia up to Ochrida and the eastern frontier of Albania?
The answer, in brief, is that it has been the undeviating policy of Bulgaria, ever since her own emancipation by Russia in 1877, to free the Bulgarians still under the Ottoman yoke and unite them in a common fatherland. The Great Bulgaria which was created by Russia in the treaty she forced on Turkey—the Treaty of San Stefano—was constructed under the influence of the idea of a union of the Bulgarian race in a single state under a common government. This treaty was afterward torn to pieces by the Congress of Berlin, which set up for the Bulgarians a very diminutive principality. But the Bulgarians, from the palace down to the meanest hut, have always been animated by that racial and national idea. The annexation of Eastern Roumelia in 1885 was a great step in the direction of its realization. And it was to carry that programme to completion that Bulgaria made war against Turkey in 1912. Her primary object was the liberation of the Bulgarians in Macedonia and their incorporation in a Great Bulgaria. And the Treaty of Partition with Servia seemed, in the event of victory over Turkey, to afford a guarantee of the accomplishment of her long-cherished purpose.