The Irish Republican Army or IRA originated from the Irish Republican Brotherhood, and fought against the British Army to get freedom for Ireland in the Irish War of Independence. The British army had invaded Ireland earlier in the plantation of Ulster and then invaded Dublin, after some time when the IRA had fought the island of Ireland was split up and the Republic of Ireland became independent, the IRA split up and some parts of it were involved in the fighting in Northern Ireland called "The Troubles". The original IRA are now named as ná Óglaigh na hÉireann. While the other IRA have used guerilla tacticts to achieve a united Ireland free from British rule.