Major Events Timeline By JKeely Period: Jan 1, 1914 to Jan 1, 1919 Major Events Timeline Jul 28, 1914 Start of World War 1 On this date, what was then called the Great War began with the assassination of Archduke Franz Ferdinand. Aug 23, 1914 Battle of Mons Nov 5, 1915 Italy declares war on Germany Dec 15, 1915 Allied withdrawal of Gallipoli Apr 2, 1917 America declares war on Germany