The July Crisis was a series of interrelated diplomatic and military escalations among the major powers of Europe in mid-1914, which led to the outbreak of World War I. It began on 28 June 1914 when the Bosnian Serb nationalist Gavrilo Princip assassinated Archduke Franz Ferdinand, heir presumptive to the Austro-Hungarian throne, and his wife Sophie, Duchess of Hohenberg. A complex web of alliances, coupled with the miscalculations of numerous political and military leaders, resulted in an outbreak of hostilities amongst most of the major European states by early August 1914.