The relationship of Greece and Bulgaria was often turbulent, and the event from 1925 tells best how little it took to escalate.
It is generally difficult to determine the exact cause of a war, but in October 1925 there was no doubt.
It was a stray dog.
At the border crossing, a playful dog managed to escape from its leash and decided to go around the area. Its owner, a Greek soldier, crossed only few steps into the Bulgarian territory to retrieve his dog.
The Bulgarian guard shot him at site. Both sides immediately opened fire, before a Greek officer, waving a white flag, reached the neutral territory, from which he called for peace.
The Bulgarians also shot him.
The new Greek military commander seemed to be waiting for this to prove himself, as he gave Bulgaria 48 hours to apologize, arrest the shooters and compensate the victims’ families. Then, without waiting for those 48 hours to expire, he attacked the Bulgarians.