World War I By restrepodm Jun 28, 1914 Assassination of Archduke Franz Ferdinand aong with his wife in Sarajevo Jul 1, 1914 Germany and the Ottoman Empire sign a secret alliance treaty Jul 5, 1914 Austria-Hungary seeks German support for a war against Serbia in case of Russian mobilization. Germany gives assurances of support Jul 23, 1914 Austria-Hungary sends an ultimatum to Serbia, and their respnse is seen as unsatisfactory Jul 28, 1914 Austria-Hungary declared war on Serbia Jul 31, 1914 Germany warns Russia to stop mobilizing Aug 1, 1914 Germany declared war on Russia Aug 1, 1914 Italy declares its neutrality Aug 3, 1914 Germany declared war on France and Belgium Aug 4, 1914 Britain declared war against Germany Aug 4, 1914 Germany's invasion of Belgium
