(1912–13), alliance of Bulgaria, Serbia, Greece (Greece, history of), and Montenegro, which fought the First Balkan War against Turkey (1912–13). Ostensibly created to limit increasing Austrian power in the Balkans, the league was actually formed at the instigation of Russia in order to expel the Turks from the Balkans. The league members declared war on the Ottoman Empire in October 1912. The league was victorious, but it disintegrated when its members quarreled over the division of their territorial spoils in Macedonia. This dispute resulted in the Second Balkan War, against Bulgaria, in 1913 (see Balkan Wars).

(1866–68), an alliance organized by the Serbian prince Michael III (Mihailo Obrenović). Concluded by the governments of Serbia, Romania, Montenegro, and Greece and a Bulgarian revolutionary society, it tried to drive the Turks from the Balkans and to unite the South Slavs in a single state. The league planned a coordinated rebellion against the Turks, but the assassination of Prince Michael (June 10, 1868) derailed the plans and destroyed the league.