When Austria-Hungary declared that it would join the war on the side of Serbia, Bulgaria withdrew from Serbia leaving the Serbo-Bulgarian border precisely where it had been prior to the war.
Kui Austria-Ungari siis kuulutas, et astub Serbia poolel sõtta, taganes Bulgaaria Serbiast, jättes Serbia-Bulgaaria piiri täpselt nii, nagu enne sõda.