Every Balkan country yearned to extend its borders. Most desired to contain every person of the appropriate ethnicity, and some to improve their position in the world by acquiring, for instance, some mines or a seaport. Fulfilling such dreams meant wresting territory from the Ottoman empire, which would never give it up without a fight. The Turks would have to be soundly beaten in battle—an impossibility for any Balkan country acting alone. Clearly, an alliance was needed. But how could it be put together when so many rivers, cities, and districts were on more than one country's wish list? The Balkan League created in 1912 was a complex affair, binding four countries together on the basis of hopes and assumptions that were often unexpressed—because if they were expressed, alliance would have been impossible. And in 1912 none of the Balkan nations wanted that.

The Balkan League succeeded in beating the Turks, who were prevented by a Greek naval blockade from reinforcing the few troops they had in Europe. The Bulgarians pushed them back nearly to Constantinople. On the other hand, the territory that Bulgaria wanted most—Macedonia—lay in the opposite direction, and was captured by the Serbs and Greeks. (A small Bulgarian force had been sent to seize Salonika, but Venizélos ensured that the Greek army got there first.) The victors celebrated, but clearly some issues remained to be worked out.

The peace conference, held in London and dominated by the Great Powers, was a disappointment to the Balkan allies. Though the Serbs had reached the Adriatic (by capturing territory almost entirely inhabited by Albanians), Italy and Austria-Hungary—both with naval interests in that sea—suddenly discovered that the cause of Albanian independence was close to their hearts, and Serbia would have to remain landlocked. Balked of their dearest wish, the Serbs naturally wanted something in compensation—something like northern Macedonia, which they were now occupying. Before the war they had promised to share it with Bulgaria, but things looked different now. As for southern Macedonia, the Greeks had taken most of it, and felt that, since the population was mainly Greek, they ought to keep it. (Their figures were probably exaggerated—most Balkan politicians at the time tended to have selective eyesight in matters of ethnicity.) Venizélos did offer the Bulgarians a compromise, but—confident that their army could trounce Greece’s any day of the week—they turned it down. Everyone realized that a second war, this time among the allies, was inevitable.

The war began when two Bulgarian armies attacked Greek and Serbian positions in Macedonia. This was apparently intended as a demonstration, but it looked enough like an offensive to fool their opponents. Both were prepared, and the Bulgarians got more than they’d bargained for. Counterattacks pushed them out of territory that had been securely Bulgarian following the first war. It took them several days to find their footing, and in the second week of the war they rallied. Meanwhile King Constantine, dreaming of a victory march in Sofía, was leading led the Greek army northward through territory that Greece had neither the desire nor the ability to keep. The reinforced enemy stopped their advance in a narrow gorge, where they fought for a week under mounting Bulgarian pressure. The exhausted Greeks were nearing surrender when a large Romanian army suddenly crossed the border into Bulgaria. Having no defense available, the Bulgarians were forced to capitulate. Romania wanted only a small piece of Bulgarian territory that it had already occupied, so Greece and Serbia were the big territorial gainers. Because everyone assumed that the original Bulgarian attack had been a full-scale, deliberate offensive, those two countries were also awarded the moral high ground.

Find out here who got what in the peace settlement, and who was able to keep it—followed by some reflections on the wars, and on War.