Mezue ahịrịokwu na-esonụ: E lere mmeri Serbia anya dị ka ihe na-agaghị ekwe omume, ma ọ dịghị ihe ọzọ site n'aka ndị na-ekiri ihe na-emenụ, ma e jiri ya tụnyere ike nke Austria-Hungary. Otú ọ dị, o doro anya na Serbia kwadebere nke ọma, na mgbe usoro nke agha na 1914-1915 (Battle of Cer,
Agha nke Kolubara), ọnwụ na iweghachite Belgrade, na mwakpo ndị Serbia na-arụ ọrụ nke ụfọdụ mpaghara Austria (na Syrmia na ọwụwa anyanwụ Bosnia), ndị agha Austria kwụsịrị. Na 5 Julaị 1914, ihe gbanwere ka agadi Eze Peter m hapụrụ ọrụ ya nye onye nketa Alexander, na-eme ya onye nnọchi ya.