Serbia bore the greatest responsibility for the outbreak of WW1. Serbian nationalism and expansionism were profoundly disruptive forces and Serbian backing for the Black Hand terrorists was extraordinarily irresponsible. read more
All of those nations are responsible for World War I. Unlike World War II in Europe, that gets firmly pinned on Germany & Italy (with some asterisks), the First World War was the fault of the nations in Europe —nearly all of them. read more
Britain was responsible in starting World War 1 because as Germany was forwarding with the Schlieffen plan which was designed by Alfred von Schlieffen, Britain did not tell German Officials that Britain had a treaty with Belgium and would have to intervene if Germany was to invade Belgium (McMeekin). read more