First Northern Ireland Parliament opened. International recognition of the border between Northern Ireland and the Irish Free State. Free State declared a republic. The Irish Republican Army launches armed campaign to reunite north and south.
Violence escalates in Northern Ireland.
Britain sends troops to Londonderry and adds forces in Belfast. Britain enforces direct rule on Northern Ireland. Widgery investigation into Bloody Sunday killings. Direct rule is reinstated after strikes by Protestant workers end power-sharing. Violence by IRA and Protestant paramilitary organizations intensifies across Ireland and Britain.