The Balkan Wars
In March 1911, against the background of increasing unrest in Macedonia, Ferdinand appointed a new government under Ivan Geshov to begin negotiations for an anti-Turkish alliance. In May 1912 Bulgaria signed a treaty with Serbia providing for military cooperation but leaving a large section of Macedonia as a contested zone, the fate of which would be determined after the war. A quickly made agreement with Greece also made no provision for the future distribution of territory. An arrangement between Greece and Serbia and verbal agreements with Montenegro completed the formation of the Balkan League. Montenegro declared war on the Ottoman Empire on September 25 (October 8), and the other Balkan states soon entered the conflict.
The successes of the Balkan League exceeded expectations. Bulgarian forces won major victories at Lozengrad (now Kırklareli) and Lüleburgaz and laid siege to Adrianople (now Edirne) and the Çatalca line of fortifications defending Constantinople, while the Greeks took Salonika (now Thessaloníki), and Serbian troops won a series of battles in Macedonia. The Ottoman Turks asked for an armistice, but Ferdinand insisted that the army attempt to capture Constantinople. When the assault on the Çatalca line failed, leaving the Bulgarian army in a weakened state, the tsar agreed to the armistice, and peace negotiations began in London.
On May 17 (May 30), 1913, the Ottoman Empire signed the Treaty of London, conceding all but a small strip of its European territory. But it proved impossible to divide the territory peacefully among the victors. Serbia and Greece insisted on retaining most of the Macedonian territory they had occupied, and Romania demanded compensation for its neutrality. When Geshov was not able to negotiate a compromise, he resigned in favour of Stoyan Danev, who reflected Ferdinand’s desire for a military solution. On the night of June 16–17 (June 29–30) Bulgarian forces began the Second Balkan War by launching a surprise assault on Greek and Serbian positions in Macedonia. As the Bulgarian attack was being repulsed, Romanian troops began an uncontested march toward Sofia from the north, and Turkey reoccupied the fortress of Adrianople.
By the Treaty of Bucharest, signed on July 28 (August 10), 1913, Romania took the rich lands of the southern Dobruja and the city of Silistra, while Serbia and Greece divided the larger part of Macedonia between them. From its gains in the First Balkan War, Bulgaria retained only a small part of eastern Macedonia, the Pirin region, and a portion of eastern Thrace. This was poor compensation for the loss of the southern Dobruja and of the Bulgarian exarchate in Macedonia. Consequently, the desire to win back what had been lost was the main motivating factor in Bulgaria’s diplomacy when World War I began.