In April of 1911 Venizelos, through a British journalist, sent an unofficial note to the Bulgarian Government suggesting an alliance against Turkey. Five months later negotiations were also commenced with Serbia, where a Serbo-Bulgarian alliance was suggested. But for a while nothing definite was done, until suddenly the bigger powers began showing signs of action. Italy, the ally of Austria, declared war on Turkey in September, 1911, with the avowed purpose of possessing herself of Tripoli.
This hurried the Balkan States. In March, 1912, Serbia and Bulgaria signed a treaty of alliance. In April Greece and Bulgaria signed a similar treaty, and a fortnight later Serbia and Greece signed another document which made the Balkan League complete, Montenegro acting in agreement with Serbia.
According to the Serbo-Bulgarian agreement, should the Turks be defeated, Bulgaria was to take the whole of the territory south and east of the Rhodope Mountains and the Struma River, while Serbia was to take that north of the Shar Mountains, including Old Serbia and Kossovo. The rest, comprising all of Macedonia, was to be established as an independent state. Should this, for any reason, be impossible, a line was to be drawn from the point at which the Bulgarian, Serbian, and Turkish frontiers met, a little northwest of Kustendil, to Struga at the north end of Lake Ochrida, leaving Kratovo, Veles, Monastir, and Ochrida to Bulgaria, all purely Slav districts, while the Czar of Russia was to act as arbitrator with regard to the rest of the region, including Kumanovo, Uskub, Krushevo, and Dibra. To this was added a clause by which Bulgaria agreed to send 200,000 men to the support of Serbia should Austria threaten her.
The agreement with Greece did not definitely provide for her share, but it was understood she should have Epirus in southern Albania, Crete, what islands in the Ægean her naval forces might capture, and a slice of the Ægean seacoast where the population was mostly Greek. Montenegro was to have what she could take from the Turkish forces in her vicinity. Albania was not mentioned, but it was understood that Serbia was to obtain her outlet on the Adriatic.
The clause in the agreement between Serbia and Bulgaria, providing for an independent Macedonia, is especially significant. It was inserted for the special consideration of Sandanski and the other Macedonian committee leaders.