The Irish Army (Irish: Arm na hÉireann) is the main branch of the Irish Defence Forces (Óglaigh na hÉireann). It was first forme in 1922 after the implementation of the Anglo-Irish Treaty and the subsequent foundation of the Irish Free State. It was originally formed from the pro-Treaty elements of the Irish Republican Army (IRA), and its first task was to defend the new Free State from the anti-Treaty IRA during the Irish Civil War.