Tensions between Greece and Bulgaria were already running dangerously high in the 1920s due to territorial disputes following World War I. On October 18, 1925, near the border town of Petrich, a simple canine mishap sparked a full-blown international crisis. A Greek soldier's dog broke loose and sprinted across the border demarcation line into Bulgarian territory.
When the soldier ran after his beloved pet, Bulgarian border guards fired upon him, killing him instantly. Outraged by the shooting, Greek troops launched an immediate counter-attack, leading to an exchange of rifle fire that killed a Greek captain. The Greek government, headed by General Theodoros Pangalos, issued an ultimatum demanding reparations and an official apology.
Before Bulgaria could formally respond, Pangalos ordered the invasion of Southwestern Bulgaria. Greek troops occupied Petrich, shelling the town and occupying several villages. Recognizing they were outmatched, the Bulgarian army refrained from heavy retaliation, instead appealing to the League of Nations for intervention.
The League acted swiftly, ordering an immediate cease-fire, a Greek withdrawal, and mandating that Greece pay forty-five thousand pounds in compensation to Bulgaria. The incident remains one of the shortest and most unusual border conflicts in modern history.