The Irish War of Independence (January 1919 - July 1921) is a guerrilla campaign mounted against the British government in Ireland by the Irish Republican Army (IRA) under the First Dáil, the Irish parliament created in 1919 by a majority of Irish MPs.It is also known as the Anglo-Irish War or the Tan War[4] The IRA that fights in this conflict is often referred to as the Old IRA to distinguish it from later organizations that will use the same name.