Greece had emerged victorious from the 1912-1913 Balkan Wars, with her territory almost doubled, but found itself in a difficult international situation. The status of the Greek-occupied eastern Aegean islands was left undetermined, and the Ottoman Empire continued to claim them, leading to a naval arms race and mass expulsions of ethnic Greeks from Anatolia. In the north, Bulgaria, defeated in the Second Balkan War, harbored revanchist plans against Greece and Serbia. The two countries were bound by a treaty of alliance which promised military assistance in case of a Bulgarian attack, but in August 1914, the danger would emerge from a different quarter altogether: the Assassination of Archduke Franz Ferdinand led to the declaration of war by Austria-Hungary on Serbia and the outbreak of the First World War.