Outbreak of War By 9wunschj Jun 28, 1914 Archduke Franz Ferdinand was assasinated in Sarajevo Jul 28, 1914 Austria-Hungary declared war on Serbia Jul 30, 1914 Russia Mobilised Aug 1, 1914 Germany declared war on Russia Aug 1, 1914 France mobilised in support of Russia Aug 2, 1914 Germany demanded access through Belgium to fight France Aug 3, 1914 Germany Declared war on France and invaded Belgium Aug 4, 1914 Britain declared war on Gemany to defend Belgium