ABSTRACT
The First World War added substantially to the store of resentments and rivalries which would prevent Balkan states and peoples cooperating in future decades. The existing states fought on different sides and invaded each other’s territory. But until the autumn of 1915 Serbia was the sole belligerent in the Balkans. A state of 4.5 million people, it succeeded for a year in repulsing an empire of fifty million. But, contrary to some expectations, the Hapsburgs were able to retain the loyalty of the South Slavs and other nationalities fighting in their army.
