Concept:
- The Balkans became dangerous because three conditions came together in one place: many peoples, a collapsing ruler, and powerful outsiders with an interest in the outcome.
- Taking the three conditions one at a time shows why war there could not stay local.
Step 1: The first condition, a crowded mix of peoples.
The region covered what are today Romania, Bulgaria, Albania, Greece, Macedonia, Croatia, Bosnia-Herzegovina, Slovenia, Serbia and Montenegro, and its people were broadly called the Slavs.
No single group could claim the whole area, and no boundary could satisfy everyone.
Step 2: The second condition, an empire losing its grip.
Much of the Balkans lay under the Ottoman Empire, which tried to save itself through modernisation and internal reform and largely failed. As its authority weakened, its European subjects broke away one after another and declared independence.
Every withdrawal of Ottoman power left a vacancy that somebody wanted to fill.
Step 3: How the newly free peoples treated each other.
Each nationality argued from history that it had once been independent and had later been subjugated, and used that argument to claim territory. The claims overlapped, so the groups grew fiercely jealous of one another, each hoping to gain at the cost of its neighbours.
Step 4: The third condition, watching great powers.
Russia, Germany, England and Austro-Hungary were already competing over trade, colonies, navies and armies. Each wanted to check the influence of the others in the Balkans and to extend its own.
So no dispute in the region stayed between the two peoples involved. Each found a powerful backer.
Step 5: How the three conditions produced a world war.
Overlapping claims guaranteed a quarrel, the Ottoman collapse guaranteed an opening, and great power rivalry guaranteed that any quarrel would draw in armies from outside. A series of wars in the region followed, and the final crisis brought the whole of Europe into the First World War.
Final Answer: The Balkans held too many rival nationalities, a ruler too weak to hold them, and great powers too eager to intervene. That combination made the region the starting point of the war of 1914.