WW1 Timeline By Drew24 Jun 28, 1914 Archduke and Archduchess visit sarajevo Jun 28, 1914 Gavrilo Princip fired two shots Jun 28, 1914 Gavrilo Princip is arrested Jul 23, 1914 Austria-Hungary sends ultimatum to Serbia Jul 25, 1914 serbia agrees to two of the three terms of the ultimatum Jul 28, 1914 Austria-Hungary declares war on serbia Jul 31, 1914 Russia mobilizes to defend Serbia Jul 31, 1914 Germany orders France and Russia to stop mobilizing Aug 1, 1914 France mobilizes to support its Russian ally Aug 3, 1914 Germany declares war on France