Question

The assassination of Archduke Franz Ferdinand of Austria-Hungary at Sarajevo on 28 June 1914 set off the July Crisis. Austria-Hungary issued an ultimatum to Serbia; after Serbia’s partial rejection, Austria-Hungary declared war on 28 July 1914. A web of mobilizations and mutual defense obligations quickly expanded the conflict: Russia mobilized for Serbia, Germany declared war on Russia (1 August) and on France (3 August), Germany invaded neutral Belgium (4 August), and Britain declared war on Germany (4 August). These steps mark the outbreak of World War I in late July–early August 1914.
(rewrite)

Answer 1

The assassination of Archduke Franz Ferdinand of Austria-Hungary in Sarajevo on 28 June 1914 touched off the July Crisis. Austria-Hungary issued an ultimatum to Serbia; after Serbia accepted some but not all of the demands, Austria-Hungary declared war on 28 July. A cascade of mobilizations and alliance obligations rapidly expanded the fighting: Russia mobilized for Serbia; Germany declared war on Russia (1 August) and on France (3 August); Germany invaded neutral Belgium (4 August); and Britain declared war on Germany that same day. These steps marked the outbreak of World War I in late July and early August 1914.